Coverage › CVE-2021-34473

CVE-2021-34473 Mapped Sigma

Microsoft Exchange Server Remote Code Execution Vulnerability

Vendor / product: Microsoft — Exchange Server
Description (CISA): Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution.
Added to KEV: 2021-11-03
Due date: 2021-11-17
Required action: Apply updates per vendor instructions.
Known ransomware use: Known
CWE: CWE-918
CISA notes: https://nvd.nist.gov/vuln/detail/CVE-2021-34473
Elsewhere: cve.org · NVD · CISA KEV · JSON

ATT&CK techniques · CTID Mappings Explorer, ATT&CK 16.1, KEV snapshot 2025-07-28

5 mapping objects across 5 techniques. exploitation technique states how the vulnerability is exploited; primary and secondary impact state what exploitation achieves. They are different claims and are labelled as such.

Technique	Mapping type	CTID comment	Status in v19.2
T1190 Exploit Public-Facing Application	exploitation technique	This is a remote code execution vulnerability that is often chained with CVE-2021-34523, a privilege escalation vulnerability. ref 1	live
T1048.003 Exfiltration Over Unencrypted Non-C2 Protocol	secondary impact	CVE-2021-34473 is a part of the ProxyShell vulnerabilities in Microsoft Exchange and CVE-2021-34473 is a code execution vulnerability that requires no user action or privileges to exploit. ref 1 · ref 2 · ref 3	live
T1053.005 Scheduled Task	primary impact	CVE-2021-34473 is a part of the ProxyShell vulnerabilities in Microsoft Exchange and CVE-2021-34473 is a code execution vulnerability that requires no user action or privileges to exploit. ref 1 · ref 2 · ref 3	live
T1136 Create Account	secondary impact	CVE-2021-34473 is a part of the ProxyShell vulnerabilities in Microsoft Exchange and CVE-2021-34473 is a code execution vulnerability that requires no user action or privileges to exploit. ref 1 · ref 2 · ref 3	live
T1486 Data Encrypted for Impact	secondary impact	CVE-2021-34473 is a part of the ProxyShell vulnerabilities in Microsoft Exchange and CVE-2021-34473 is a code execution vulnerability that requires no user action or privileges to exploit. ref 1 · ref 2 · ref 3	live

Detection chain · ATT&CK Enterprise v19.2 detection strategies, analytics, log sources

T1048.003 Exfiltration Over Unencrypted Non-C2 Protocol secondary impact

DET0149 Detection of Exfiltration Over Unencrypted Non-C2 Protocol
AN0423 Windows
Detects data access or staging events followed by outbound data flows using unencrypted protocols (e.g., FTP, HTTP) initiated by unexpected processes or to rare destinations.

WinEventLog:Sysmon EventCode=3, 22 → DC0082 Network Connection Creation
WinEventLog:Sysmon EventCode=1 → DC0032 Process Creation
WinEventLog:Security EventCode=4663, 4670, 4656 → DC0055 File Access
NSM:Flow http.log, ftp.log → DC0085 Network Traffic Content

Tunable: UnencryptedProtocolList DataTransferSizeThreshold ParentProcessDenylist

AN0424 Linux
Detects file access or compression utilities followed by outbound connections using curl, wget, ftp, or custom binaries communicating over unencrypted protocols.

auditd:SYSCALL execve → DC0032 Process Creation
auditd:SYSCALL connect → DC0082 Network Connection Creation
NSM:Flow http.log, ftp.log → DC0085 Network Traffic Content
NSM:Flow flow records → DC0078 Network Traffic Flow

Tunable: SensitiveDirectoryWatchlist ProcessBaseline TimeWindow

AN0425 macOS
Detects abnormal outbound HTTP/FTP connections by local scripts or binaries outside of standard browser activity, following access to local documents or user data.

macos:osquery socket_events → DC0078 Network Traffic Flow
macos:osquery process_events → DC0032 Process Creation
macos:unifiedlog log stream - file subsystem → DC0055 File Access
NSM:Flow http.log, ftp.log → DC0085 Network Traffic Content

Tunable: ScriptedClientAllowlist PayloadInspectionKeywordList

AN0426 ESXi
Detects shell-based scripts accessing configuration files or snapshots and transmitting them over unencrypted protocols such as FTP or HTTP to non-management IPs.

esxi:hostd event stream → DC0064 Command Execution
NSM:Flow flow records → DC0078 Network Traffic Flow
NSM:Flow http.log → DC0085 Network Traffic Content

Tunable: VMConfigAccessPathWatchlist OutboundProtocolProfile

AN0427 Network Devices
Detects use of unencrypted protocols (e.g., TFTP, FTP, HTTP) to transfer configuration files, routing tables, or logs to untrusted IP addresses, especially using administrative commands like copy run ftp:.

networkdevice:cli CLI command logs → DC0064 Command Execution
networkdevice:syslog flow records → DC0078 Network Traffic Flow
NSM:Flow PCAP inspection → DC0085 Network Traffic Content

Tunable: ProtocolCommandWatchlist DestinationIPBlocklist

Sigma rules tagged `attack.t1048.003` (9)

WebDav Client Execution Via Rundll32.EXE mediumtest

Author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research) · 2020-05-02 (modified 2023-09-18) · logsource: product=windows category=process_creation · 2dbd9d3d-9e27-42a8-b8df-f13825c6c3d5

Detects "svchost.exe" spawning "rundll32.exe" with command arguments like "C:\windows\system32\davclnt.dll,DavSetCookie". This could be an indicator of exfiltration or use of WebDav to launch code (hosted on a WebDav server).

Techniques: T1048.003

Python WebServer Execution - Linux mediumexperimental

Author: Mohamed LAKRI · 2025-10-17 · logsource: product=linux category=process_creation · 3f0f5957-04f8-4792-ad89-192b0303bde6

Detects the execution of Python web servers via command line interface (CLI). After gaining access to target systems, adversaries may use Python's built-in HTTP server modules to quickly establish a web server without requiring additional software. This technique is commonly used in post-exploitation scenarios as it provides a simple method for transferring files between the compromised host and attacker-controlled systems.

Techniques: T1048.003

Suspicious DNS Query with B64 Encoded String mediumtest

Author: Florian Roth (Nextron Systems) · 2018-05-10 (modified 2022-10-09) · logsource: category=dns · 4153a907-2451-4e4f-a578-c52bb6881432

Detects suspicious DNS queries using base64 encoding

Techniques: T1048.003 T1071.004

PowerShell ICMP Exfiltration mediumtest

Author: Bartlomiej Czyz @bczyz1, oscd.community · 2020-10-10 (modified 2022-12-25) · logsource: product=windows category=ps_script · 4c4af3cd-2115-479c-8193-6b8bfce9001c

Detects Exfiltration Over Alternative Protocol - ICMP. Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other than that of the existing command and control channel.

Techniques: T1048.003

WebDav Put Request lowtest

Author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research) · 2020-05-02 (modified 2024-03-13) · logsource: product=zeek service=http · 705072a5-bb6f-4ced-95b6-ecfa6602090b

A General detection for WebDav user-agent being used to PUT files on a WebDav network share. This could be an indicator of exfiltration.

Techniques: T1048.003

Suspicious WebDav Client Execution Via Rundll32.EXE hightest

Author: Nasreddine Bencherchali (Nextron Systems), Florian Roth (Nextron Systems) · 2023-03-16 (modified 2023-09-18) · logsource: product=windows category=process_creation · 982e9f2d-1a85-4d5b-aea4-31f5e97c6555

Detects "svchost.exe" spawning "rundll32.exe" with command arguments like C:\windows\system32\davclnt.dll,DavSetCookie. This could be an indicator of exfiltration or use of WebDav to launch code (hosted on WebDav Server) or potentially a sign of exploitation of CVE-2023-23397

Techniques: T1048.003

CVE tags: CVE-2023-23397

Suspicious Outbound SMTP Connections mediumtest

Author: frack113 · 2022-01-07 (modified 2022-09-21) · logsource: product=windows category=network_connection · 9976fa64-2804-423c-8a5b-646ade840773

Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.

Techniques: T1048.003

Potential Data Exfiltration Over SMTP Via Send-MailMessage Cmdlet mediumtest

Author: frack113 · 2022-09-26 (modified 2024-11-01) · logsource: product=windows category=ps_script · 9a7afa56-4762-43eb-807d-c3dc9ffe211b

Detects the execution of a PowerShell script with a call to the "Send-MailMessage" cmdlet along with the "-Attachments" flag. This could be a potential sign of data exfiltration via Email. Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.

Techniques: T1048.003

Data Exfiltration with Wget mediumtest

Author: Pawel Mazur · 2021-11-18 (modified 2022-12-25) · logsource: product=linux service=auditd · cb39d16b-b3b6-4a7a-8222-1cf24b686ffc

Detects attempts to post the file with the usage of wget utility. The adversary can bypass the permission restriction with the misconfigured sudo permission for wget utility which could allow them to read files like /etc/shadow.

Techniques: T1048.003

T1053.005 Scheduled Task primary impact

DET0441 Detection of Suspicious Scheduled Task Creation and Execution on Windows
AN1221 Windows
Detects the creation, modification, or deletion of scheduled tasks through Task Scheduler, WMI, PowerShell, or API-based methods followed by execution from svchost.exe or taskeng.exe. Includes detection of hidden or anomalous scheduled tasks, especially those created under SYSTEM or suspicious user contexts.

WinEventLog:Security EventCode=4698 → DC0001 Scheduled Job Creation
WinEventLog:Security EventCode=4702 → DC0012 Scheduled Job Modification
WinEventLog:Sysmon EventCode=1 → DC0032 Process Creation
WinEventLog:Sysmon EventCode=11 → DC0039 File Creation
WinEventLog:Sysmon EventCode=13, 14 → DC0063 Windows Registry Key Modification

Tunable: TimeWindow UserContext TaskNamePattern CommandLineEntropyThreshold

Sigma rules tagged `attack.t1053.005` (51)

ChromeLoader Malware Execution hightest

Author: @kostastsale · 2022-01-10 · logsource: product=windows category=process_creation · 0a74c5a9-1b71-4475-9af2-7829d320d5c2

Detects execution of ChromeLoader malware via a registered scheduled task

Techniques: T1053.005 T1059.001 T1176

Suspicious Modification Of Scheduled Tasks hightest

Author: Nasreddine Bencherchali (Nextron Systems) · 2022-07-28 (modified 2022-11-18) · logsource: product=windows category=process_creation · 1c0e41cd-21bb-4433-9acc-4a2cd6367b9b

Detects when an attacker tries to modify an already existing scheduled tasks to run from a suspicious location Attackers can create a simple looking task in order to avoid detection on creation as it's often the most focused on Instead they modify the task after creation to include their malicious payload

Techniques: T1053.005

Operation Wocao Activity hightest

Author: Florian Roth (Nextron Systems), frack113 · 2019-12-20 (modified 2022-10-09) · logsource: product=windows category=process_creation · 1cfac73c-be78-4f9a-9b08-5bde0c3953ab

Detects activity mentioned in Operation Wocao report

Techniques: T1012 T1036.004 T1027 T1053.005 T1059.001

Scheduled Task Creation with Curl and PowerShell Execution Combo mediumexperimental

Author: Swachchhanda Shrawan Poudel (Nextron Systems) · 2025-02-05 · logsource: product=windows category=process_creation · 1d174d38-8fda-4081-a9b6-56d9763c0cd8

Detects the creation of a scheduled task using schtasks.exe, potentially in combination with curl for downloading payloads and PowerShell for executing them. This facilitates executing malicious payloads or connecting with C&C server persistently without dropping the malware sample on the host.

Techniques: T1053.005 T1218 T1105

Suspicious Schtasks Schedule Types hightest

Author: Nasreddine Bencherchali (Nextron Systems) · 2022-09-09 · logsource: product=windows category=process_creation · 24c8392b-aa3c-46b7-a545-43f71657fe98

Detects scheduled task creations or modification on a suspicious schedule type

Techniques: T1053.005

Potential SSH Tunnel Persistence Install Using A Scheduled Task highexperimental

Author: Rory Duncan · 2025-07-14 · logsource: product=windows category=process_creation · 2daa93a0-a5fb-41c5-8cd8-3c11294bfd1f

Detects the creation of new scheduled tasks via commandline, using Schtasks.exe. This rule detects tasks creating that call OpenSSH, which may indicate the creation of reverse SSH tunnel to the attacker's server.

Techniques: T1053.005

Powershell Create Scheduled Task mediumtest

Author: frack113 · 2021-12-28 (modified 2025-10-07) · logsource: product=windows category=ps_script · 363eccc0-279a-4ccf-a3ab-24c2e63b11fb

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code

Techniques: T1053.005

Suspicious Scheduled Task Creation Involving Temp Folder hightest

Author: Florian Roth (Nextron Systems) · 2021-03-11 (modified 2022-10-09) · logsource: product=windows category=process_creation · 39019a4e-317f-4ce3-ae63-309a8c6b53c5

Detects the creation of scheduled tasks that involves a temporary folder and runs only once

Techniques: T1053.005

Suspicious Scheduled Task Creation hightest

Author: Nasreddine Bencherchali (Nextron Systems) · 2022-12-05 (modified 2022-12-07) · logsource: product=windows service=security · 3a734d25-df5c-4b99-8034-af1ddb5883a4

Detects suspicious scheduled task creation events. Based on attributes such as paths, commands line flags, etc.

Techniques: T1053.005

Diamond Sleet APT Scheduled Task Creation criticaltest

Author: Nasreddine Bencherchali (Nextron Systems) · 2023-10-24 · logsource: product=windows service=security · 3b8e5084-4de9-449a-a40d-0e11014f2e2d

Detects registry event related to the creation of a scheduled task used by Diamond Sleet APT during exploitation of Team City CVE-2023-42793 vulnerability

Techniques: T1053.005

Task Scheduler DLL Loaded By Application Located In Potentially Suspicious Location lowtest

Author: Swachchhanda Shrawan Poudel · 2024-09-02 · logsource: product=windows category=image_load · 3b92a1d0-8d4b-4d28-a1b4-1e29d49a6a3e

Detects the loading of the "taskschd.dll" module from a process that located in a potentially suspicious or uncommon directory. The loading of this DLL might indicate that the application have the capability to create a scheduled task via the "Schedule.Service" COM object. Investigation of the loading application and its behavior is required to determining if its malicious.

Techniques: T1053.005

Scheduled Task Executed From A Suspicious Location mediumtest

Author: Nasreddine Bencherchali (Nextron Systems) · 2022-12-05 (modified 2023-02-07) · logsource: product=windows service=taskscheduler · 424273ea-7cf8-43a6-b712-375f925e481f

Detects the execution of Scheduled Tasks where the Program being run is located in a suspicious location or it's an unusale program to be run from a Scheduled Task

Techniques: T1053.005

Scheduled TaskCache Change by Uncommon Program hightest

Author: Syed Hasan (@syedhasan009) · 2021-06-18 (modified 2025-10-22) · logsource: product=windows category=registry_set · 4720b7df-40c3-48fd-bbdf-fd4b3c464f0d

Monitor the creation of a new key under 'TaskCache' when a new scheduled task is registered by a process that is not svchost.exe, which is suspicious

Techniques: T1053 T1053.005

Scheduled Task Deletion lowtest

Author: David Strassegger, Tim Shelton · 2021-01-22 (modified 2023-01-20) · logsource: product=windows service=security · 4f86b304-3e02-40e3-aa5d-e88a167c9617

Detects scheduled task deletion events. Scheduled tasks are likely to be deleted if not used for persistence. Malicious Software often creates tasks directly under the root node e.g. \TASKNAME

Techniques: T1053.005

OilRig APT Schedule Task Persistence - System criticaltest

Author: Florian Roth (Nextron Systems), Markus Neis, Jonhnathan Ribeiro, Daniil Yugoslavskiy, oscd.community · 2018-03-23 (modified 2023-03-08) · logsource: product=windows service=system · 53ba33fd-3a50-4468-a5ef-c583635cfa92

Detects OilRig schedule task persistence as reported by Nyotron in their March 2018 report

Techniques: T1053.005 T1543.003 T1112 T1071.004

All 51 rules on the technique page →

T1136 Create Account secondary impact

DET0583 Detection Strategy for T1136 - Create Account across platforms
AN1604 Windows
Adversary uses built-in OS tools or API calls to create local or domain accounts for persistence or lateral movement. Tools such as 'net user', PowerShell, or MMC snap-ins may be used. Detection focuses on Event ID 4720 paired with process lineage and user context.

WinEventLog:Security EventCode=4720 → DC0014 User Account Creation
WinEventLog:Sysmon EventCode=1 → DC0032 Process Creation

Tunable: TimeWindow ParentProcessName UserContext

AN1605 Linux
Adversary invokes 'useradd', 'adduser', or equivalent system commands or scripts to create local users. Detection focuses on command execution and audit trail of passwd/shadow file modifications.

auditd:SYSCALL useradd or adduser executed → DC0014 User Account Creation
auditd:SYSCALL chmod/chown to /etc/passwd or /etc/shadow → DC0061 File Modification

Tunable: BinaryPath ExecutionTime

AN1606 macOS
Adversary creates new users using 'dscl' commands, GUI tools, or by modifying user plist files. Detection includes monitoring dscl invocation and user-related plist changes.

macos:unifiedlog dscl . -create → DC0064 Command Execution
macos:unifiedlog modification to /var/db/dslocal/nodes/Default/users/ → DC0061 File Modification

Tunable: UsernamePattern ExecutionSource

AN1607 Identity Provider
Adversary creates users via IAM/IdP API or portal (e.g., Azure AD, Okta). Detection involves monitoring API calls, admin action logs, and correlation with role assignments.

azure:audit Add user → DC0014 User Account Creation

Tunable: AdminThreshold AutomationExemptions

AN1608 IaaS
Account creation via cloud service APIs or CLI, often associated with key generation. Monitored via CloudTrail or equivalent audit logs.

AWS:CloudTrail CreateUser → DC0014 User Account Creation
AWS:CloudTrail AttachUserPolicy → DC0010 User Account Modification

Tunable: Region ServiceScope

Sigma rules tagged `attack.t1136` (3)

AWS ElastiCache Security Group Created lowtest

Author: Austin Songer @austinsonger · 2021-07-24 (modified 2022-10-09) · logsource: product=aws service=cloudtrail · 4ae68615-866f-4304-b24b-ba048dfa5ca7

Detects when an ElastiCache security group has been created.

Techniques: T1136 T1136.003

ESXi Account Creation Via ESXCLI mediumtest

Author: Cedric Maurugeon · 2023-08-22 · logsource: product=linux category=process_creation · b28e4eb3-8bbc-4f0c-819f-edfe8e2f25db

Detects user account creation on ESXi system via esxcli

Techniques: T1136 T1059.012

New Kubernetes Service Account Created lowtest

Author: Leo Tsaousis (@laripping) · 2024-03-26 · logsource: product=kubernetes category=application service=audit · e31bae15-83ed-473e-bf31-faf4f8a17d36

Detects creation of new Kubernetes service account, which could indicate an attacker's attempt to persist within a cluster.

Techniques: T1136

T1190 Exploit Public-Facing Application exploitation technique

DET0080 Exploit Public-Facing Application – multi-signal correlation (request → error → post-exploit process/egress)
AN0219 Windows
Adversary sends crafted HTTP/S (or other service) input to an Internet-facing app (IIS/ASP.NET, API, device portal). Chain: (1) abnormal request patterns to public endpoint → (2) elevated 4xx/5xx or unusual methods/paths → (3) server process (w3wp.exe/other service) spawns shell/LOLbins or loads non-standard modules → (4) optional outbound callback from the host/container.

ApplicationLog:IIS IIS W3C logs in C:\inetpub\logs\LogFiles\W3SVC* (spikes in 5xx, RCE/SQLi/path traversal/JNDI patterns) → DC0038 Application Log Content
WinEventLog:Sysmon EventCode=1 → DC0032 Process Creation
WinEventLog:Sysmon EventCode=7 → DC0016 Module Load
WinEventLog:Sysmon EventCode=3, 22 → DC0082 Network Connection Creation

Tunable: PublicVIPs SuspiciousPatterns ErrorRateThreshold TimeWindow AllowedChildList

AN0220 Linux
Adversary exploits Apache/Nginx/app servers. Chain: (1) suspicious requests in access logs → (2) spike of 5xx or WAF blocks → (3) web server or interpreter (apache2/nginx/php-fpm/node/python) spawns /bin/sh, curl, wget, socat, or writes webshell → (4) outbound callback.

ApplicationLog:WebServer /var/log/httpd/access_log, /var/log/apache2/access.log, /var/log/nginx/access.log with exploit indicators and burst errors → DC0038 Application Log Content
auditd:SYSCALL execve → DC0032 Process Creation
NSM:Flow HTTP payloads with SQLi/LFI/JNDI/deserialization indicators → DC0085 Network Traffic Content

Tunable: WebProcList ChildToolList BurstThreshold TimeWindow

AN0221 macOS
Adversary targets macOS-hosted public services (e.g., nginx, node). Chain: suspicious inbound request → service crash/5xx → service spawns shell or writes file → new outbound connection.

macos:unifiedlog App/web server logs ingested via unified logging or filebeat (nginx/apache/node). → DC0038 Application Log Content
macos:unifiedlog exec events where web process starts a shell/tooling → DC0032 Process Creation
NSM:Flow outbound egress from web host after suspicious request → DC0085 Network Traffic Content

Tunable: ServiceList TimeWindow

AN0222 Containers
Adversary exploits containerized app via ingress or service. Chain: (1) suspicious request in ingress/app logs → (2) container process spawns a shell/exec/sidecar (kubectl exec/docker exec) → (3) egress to Internet or metadata service (169.254.169.254).

ApplicationLog:Ingress Kubernetes NGINX/Envoy ingress controller logs with anomalous payloads and 5xx spikes → DC0038 Application Log Content
docker:events Docker/Kubernetes audit of exec/attach (kubectl exec) or unexpected child processes inside container → DC0032 Process Creation
NSM:Flow Requests towards cloud metadata or command & control from pod IPs → DC0085 Network Traffic Content

Tunable: IngressNamespaces MetadataEndpoints TimeWindow

AN0223 IaaS
Adversary targets cloud-hosted public endpoints. Chain: (1) ALB/ELB/Cloud LB logs show exploit-like inputs or error spikes → (2) workload spawns shell or reaches metadata API → (3) egress to new external hosts.

ALB:HTTPLogs AWS ALB/ELB/GCP/Azure Application Gateway HTTP logs with unusual methods, long URIs, serialized payloads, 4xx/5xx bursts → DC0085 Network Traffic Content
AWS:VPCFlowLogs VPC/NSG flow logs for pod/instance egress to Internet or metadata → DC0078 Network Traffic Flow

Tunable: LBProjects ErrorBurst

AN0224 ESXi
Adversary exploits exposed OpenSLP on ESXi or vCenter public endpoints. Chain: inbound request pattern to mgmt service → hostd/vpxd error/crash/restart → unexpected process behavior or datastore access → outbound callback.

esxi:hostd /var/log/hostd.log anomalies (faults, crashes, restarts) around inbound connections → DC0038 Application Log Content
NSM:Flow Connections to TCP 427 (SLP) or vCenter web services from untrusted sources → DC0085 Network Traffic Content

Tunable: MgmtCIDR TimeWindow

AN0225 Network Devices
Adversary exploits public admin services on routers/firewalls/switches. Chain: anomalous HTTP/SNMP/SmartInstall inputs → device syslog errors/restarts → config changes/CLI spawn → egress to attacker C2.

networkdevice:controlplane Syslog from edge devices with HTTP 500s on mgmt portal, SmartInstall events, unexpected CLI commands → DC0038 Application Log Content
NSM:Flow NetFlow/sFlow for odd egress to Internet from mgmt plane → DC0085 Network Traffic Content

Tunable: MgmtPorts TrustedAdmins

Sigma rules tagged `attack.t1190` (149)

Potential CVE-2023-25717 Exploitation Attempt hightest

Author: Nasreddine Bencherchali (Nextron Systems) · 2023-05-30 · logsource: category=webserver · 043c1609-0e32-4462-a6f2-5a0c2da3fafe

Detects a potential exploitation attempt of CVE-2023-25717 a Remote Code Execution via an unauthenticated HTTP GET Request, in Ruckus Wireless Admin

Techniques: T1190

CVE tags: CVE-2023-25717

Potential CVE-2021-27905 Exploitation Attempt mediumtest

Author: @gott_cyber · 2022-12-11 (modified 2023-03-24) · logsource: category=webserver · 0bbcd74b-0596-41a4-94a0-4e88a76ffdb3

Detects exploitation attempt of the CVE-2021-27905 which affects all Apache Solr versions prior to and including 8.8.1.

Techniques: T1190

CVE tags: CVE-2021-27905

Citrix ADS Exploitation CVE-2020-8193 CVE-2020-8195 criticaltest

Author: Florian Roth (Nextron Systems) · 2020-07-10 (modified 2023-01-02) · logsource: category=webserver · 0d0d9a8a-a49e-4e27-b061-7ce4b936cfb7

Detects exploitation attempt against Citrix Netscaler, Application Delivery Controller (ADS) and Citrix Gateway exploiting vulnerabilities reported as CVE-2020-8193 and CVE-2020-8195

Techniques: T1190

CVE tags: CVE-2020-8193CVE-2020-8195

Ruby on Rails Framework Exceptions mediumstable

Author: Thomas Patzke · 2017-08-06 (modified 2020-09-01) · logsource: product=ruby_on_rails category=application · 0d2c3d4c-4b48-4ac3-8f23-ea845746bb1a

Detects suspicious Ruby on Rails exceptions that could indicate exploitation attempts

Techniques: T1190

Potential CVE-2023-23752 Exploitation Attempt hightest

Author: Bhabesh Raj · 2023-02-23 · logsource: category=webserver · 0e1ebc5a-15d0-4bf6-8199-b2535397433a

Detects the potential exploitation attempt of CVE-2023-23752 an Improper access check, in web service endpoints in Joomla

Techniques: T1190

CVE tags: CVE-2023-23752

Potential Exploitation of CrushFTP RCE Vulnerability (CVE-2025-54309) highexperimental

Author: Nisarg Suthar · 2025-08-01 · logsource: product=windows category=process_creation · 0fdc7c7f-c690-4217-9ae3-31f5156eed72

Detects suspicious child processes created by CrushFTP. It could be an indication of exploitation of a RCE vulnerability such as CVE-2025-54309.

Techniques: T1059.001 T1059.003 T1068 T1190

CVE tags: CVE-2025-54309

Terminal Service Process Spawn hightest

Author: Florian Roth (Nextron Systems) · 2019-05-22 (modified 2023-01-25) · logsource: product=windows category=process_creation · 1012f107-b8f1-4271-af30-5aed2de89b39

Detects a process spawned by the terminal service server process (this could be an indicator for an exploitation of CVE-2019-0708)

Techniques: T1190 T1210

RDS Database Security Group Modification mediumtest

Author: jamesc-grafana · 2024-07-11 · logsource: product=aws service=cloudtrail · 14f3f1c8-02d5-43a2-a191-91ffb52d3015

Detects changes to the security group entries for RDS databases. This can indicate that a misconfiguration has occurred which potentially exposes the database to the public internet, a wider audience within the VPC or that removal of valid rules has occurred which could impact the availability of the database to legitimate services and users.

Techniques: T1190

Cisco ASA Exploitation Activity - Proxy highexperimental

Author: Swachchhanda Shrawan Poudel (Nextron Systems) · 2025-11-20 · logsource: category=proxy · 15697955-6a29-47ca-92e9-0e05efae3260

Detects suspicious requests to Cisco ASA WebVpn via proxy logs associated with CVE-2025-20333 and CVE-2025-20362 exploitation.

Techniques: T1190

CVE tags: CVE-2025-20333CVE-2025-20362

TerraMaster TOS CVE-2020-28188 hightest

Author: Bhabesh Raj · 2021-01-25 (modified 2023-01-02) · logsource: category=webserver · 15c312b9-00d0-4feb-8870-7d940a4bdc5e

Detects the exploitation of the TerraMaster TOS vulnerability described in CVE-2020-28188

Techniques: T1190

CVE tags: CVE-2020-28188

Potential Server Side Template Injection In Velocity hightest

Author: Moti Harmats · 2023-02-11 · logsource: product=velocity category=application · 16c86189-b556-4ee8-b4c7-7e350a195a4f

Detects exceptions in velocity template renderer, this most likely happens due to dynamic rendering of user input and may lead to RCE.

Techniques: T1190

CVE-2021-21972 VSphere Exploitation hightest

Author: Bhabesh Raj · 2021-02-24 (modified 2023-01-02) · logsource: category=webserver · 179ed852-0f9b-4009-93a7-68475910fd86

Detects the exploitation of VSphere Remote Code Execution vulnerability as described in CVE-2021-21972

Techniques: T1190

CVE tags: CVE-2021-21972

Potential OWASSRF Exploitation Attempt - Webserver hightest

Author: Nasreddine Bencherchali (Nextron Systems) · 2022-12-22 (modified 2023-01-02) · logsource: category=webserver · 181f49fa-0b21-4665-a98c-a57025ebb8c7

Detects exploitation attempt of the OWASSRF variant targeting exchange servers It uses the OWA endpoint to access the powershell backend endpoint

Techniques: T1190

Suspicious User-Agents Related To Recon Tools mediumtest

Author: Nasreddine Bencherchali (Nextron Systems), Tim Shelton · 2022-07-19 (modified 2026-06-11) · logsource: category=webserver · 19aa4f58-94ca-45ff-bc34-92e533c0994a

Detects known suspicious (default) user-agents related to scanning/recon tools

Techniques: T1190

Python SQL Exceptions mediumstable

Author: Thomas Patzke · 2017-08-12 (modified 2020-09-01) · logsource: product=python category=application · 19aefed0-ffd4-47dc-a7fc-f8b1425e84f9

Generic rule for SQL exceptions in Python according to PEP 249

Techniques: T1190

All 149 rules on the technique page →

T1486 Data Encrypted for Impact secondary impact

DET0215 Detection of Multi-Platform File Encryption for Impact
AN0602 Windows
High-frequency file write operations using uncommon extensions, followed by ransom note creation, registry tampering, or shadow copy deletion. Often uses CLI tools like vssadmin, wbadmin, cipher, or PowerShell.

WinEventLog:Sysmon EventCode=1 → DC0032 Process Creation
WinEventLog:Sysmon EventCode=11 → DC0039 File Creation
WinEventLog:Sysmon EventCode=2 → DC0061 File Modification

Tunable: FileExtension TargetFolder TimeWindow CommandLine

AN0603 Linux
Encryption via custom or open-source tools (e.g., openssl, gpg, aescrypt) recursively targeting user or system directories. Also includes overwrite of existing data and ransom note drops.

auditd:SYSCALL openat, write, rename, unlink → DC0061 File Modification
auditd:SYSCALL execve → DC0032 Process Creation

Tunable: FilenamePattern SyscallBurstRate DirectoryTargeted

AN0604 macOS
Userland or kernel-level ransomware encrypting user files (Documents, Desktop) using srm, gpg, or compiled payloads. Often correlated with ransom note creation in multiple directories.

macos:unifiedlog file encrypted|new file with .encrypted extension|disk write burst → DC0061 File Modification
macos:unifiedlog exec srm|exec openssl|exec gpg → DC0032 Process Creation

Tunable: ExtensionPattern VolumeTargeted

AN0605 ESXi
Ransomware encrypts .vmdk, .vmx, .log, or VM config files in VMFS datastores. May rename to .locked or delete/overwrite with encrypted versions. Often correlates with shell commands run through dcui, SSH, or vSphere.

esxi:vmkernel rename .vmdk to .*.locked|datastore write spike → DC0061 File Modification
esxi:shell openssl|tar|dd → DC0064 Command Execution

Tunable: FileType UserContext

AN0606 IaaS
Encryption of cloud storage objects (e.g., S3 buckets) via Server-Side Encryption (SSE-C) or by replacing objects with encrypted variants. May include API patterns like PutObject with SSE-C headers.

AWS:CloudTrail PutObject (with SSE-C), UploadPart (SSE-C) → DC0023 Cloud Storage Modification

Tunable: SSEHeader AffectedBucket UserAgent

Sigma rules tagged `attack.t1486` (16)

Suspicious Reg Add BitLocker hightest

Author: frack113 · 2021-11-15 (modified 2022-09-09) · logsource: product=windows category=process_creation · 0e0255bf-2548-47b8-9582-c0955c9283f5

Detects suspicious addition to BitLocker related registry keys via the reg.exe utility

Techniques: T1486

AWS KMS Imported Key Material Usage highexperimental

Author: toopricey · 2025-10-18 · logsource: product=aws service=cloudtrail · 1279262f-1464-422f-ac0d-5b545320c526

Detects the import or deletion of key material in AWS KMS, which can be used as part of ransomware attacks. This activity is uncommon and provides a high certainty signal.

Techniques: T1486 T1608.003

AWS EC2 Disable EBS Encryption mediumstable

Author: Sittikorn S · 2021-06-29 (modified 2021-08-20) · logsource: product=aws service=cloudtrail · 16124c2d-e40b-4fcc-8f2c-5ab7870a2223

Identifies disabling of default Amazon Elastic Block Store (EBS) encryption in the current region. Disabling default encryption does not change the encryption status of your existing volumes.

Techniques: T1486 T1565

FunkLocker Ransomware File Creation highexperimental

Author: Saiprashanth Pulisetti ( @Prashanthblogs) · 2025-08-08 · logsource: product=windows category=file_event · 2c76a22b-702d-48fd-8fa9-e41e2fe203b3

Detects the creation of files with the ".funksec" extension, which is appended to encrypted files by the FunkLocker ransomware.

Techniques: T1486

Load Of RstrtMgr.DLL By An Uncommon Process lowtest

Author: Luc Génaux · 2023-11-28 (modified 2026-07-28) · logsource: product=windows category=image_load · 3669afd2-9891-4534-a626-e5cf03810a61

Detects the load of RstrtMgr DLL (Restart Manager) by an uncommon process. This library has been used during ransomware campaigns to kill processes that would prevent file encryption by locking them (e.g. Conti ransomware, Cactus ransomware). It has also recently been seen used by the BiBi wiper for Windows. It could also be used for anti-analysis purposes by shut downing specific processes.

Techniques: T1486 T1685

WannaCry Ransomware Activity criticaltest

Author: Florian Roth (Nextron Systems), Tom U. @c_APT_ure (collection), oscd.community, Jonhnathan Ribeiro · 2019-01-16 (modified 2025-10-18) · logsource: product=windows category=process_creation · 41d40bff-377a-43e2-8e1b-2e543069e079

Detects WannaCry ransomware activity

Techniques: T1210 T1083 T1222.001 T1486 T1490

Antivirus - Ransomware Signature criticaltest

Author: Florian Roth (Nextron Systems), Arnim Rupp · 2022-05-12 (modified 2026-06-15) · logsource: category=antivirus · 4c6ca276-d4d0-4a8c-9e4c-d69832f8671f

Detects a highly relevant Antivirus alert that reports ransomware. This event must not be ignored just because the AV has blocked the malware but investigate, how it came there in the first place.

Techniques: T1486

Potential Conti Ransomware Activity criticaltest

Author: frack113 · 2021-10-12 (modified 2023-02-13) · logsource: product=windows category=process_creation · 689308fc-cfba-4f72-9897-796c1dc61487

Detects a specific command used by the Conti ransomware group

Techniques: T1486

LockerGoga Ransomware Activity criticalstable

Author: Vasiliy Burov, oscd.community · 2020-10-18 (modified 2023-02-03) · logsource: product=windows category=process_creation · 74db3488-fd28-480a-95aa-b7af626de068

Detects LockerGoga ransomware activity via specific command line.

Techniques: T1486

Portable Gpg.EXE Execution mediumtest

Author: frack113, Nasreddine Bencherchali (Nextron Systems) · 2023-08-06 (modified 2023-11-10) · logsource: product=windows category=process_creation · 77df53a5-1d78-4f32-bc5a-0e7465bd8f41

Detects the execution of "gpg.exe" from uncommon location. Often used by ransomware and loaders to decrypt/encrypt data.

Techniques: T1486

Load Of RstrtMgr.DLL By A Suspicious Process hightest

Author: Luc Génaux · 2023-11-28 · logsource: product=windows category=image_load · b48492dc-c5ef-4572-8dff-32bc241c15c8

Detects the load of RstrtMgr DLL (Restart Manager) by a suspicious process. This library has been used during ransomware campaigns to kill processes that would prevent file encryption by locking them (e.g. Conti ransomware, Cactus ransomware). It has also recently been seen used by the BiBi wiper for Windows. It could also be used for anti-analysis purposes by shut downing specific processes.

Techniques: T1486 T1685

Microsoft 365 - Potential Ransomware Activity mediumtest

Author: austinsonger · 2021-08-19 (modified 2022-10-09) · logsource: product=m365 service=threat_management · bd132164-884a-48f1-aa2d-c6d646b04c69

Detects when a Microsoft Cloud App Security reported when a user uploads files to the cloud that might be infected with ransomware.

Techniques: T1486

Suspicious Creation TXT File in User Desktop mediumtest

Author: frack113 · 2021-12-26 (modified 2026-01-09) · logsource: product=windows category=file_event · caf02a0a-1e1c-4552-9b48-5e070bd88d11

Detects creation of .txt files in user desktop folders via cmd.exe. This behavior may indicate ransomware deploying ransom notes, but can also occur during legitimate administrative tasks. Analysts should investigate for suspicious filenames (e.g., "RANSOM", "DECRYPT", "READ_ME"), bulk file creation patterns, or concurrent encryption activity to determine if this is part of a ransomware attack.

Techniques: T1486

Suspicious Appended Extension mediumtest

Author: frack113 · 2022-07-16 (modified 2023-11-11) · logsource: product=windows category=file_rename · e3f673b3-65d1-4d80-9146-466f8b63fa99

Detects file renames where the target filename uses an uncommon double extension. Could indicate potential ransomware activity renaming files and adding a custom extension to the encrypted files, such as ".jpg.crypted", ".docx.locky", etc.

Techniques: T1486

Renamed Gpg.EXE Execution hightest

Author: Nasreddine Bencherchali (Nextron Systems), frack113 · 2023-08-09 · logsource: product=windows category=process_creation · ec0722a3-eb5c-4a56-8ab2-bf6f20708592

Detects the execution of a renamed "gpg.exe". Often used by ransomware and loaders to decrypt/encrypt data.

Techniques: T1486

All 16 rules on the technique page →

CVE-2021-34473 Mapped Sigma

ATT&CK techniques · CTID Mappings Explorer, ATT&CK 16.1, KEV snapshot 2025-07-28

Detection chain · ATT&CK Enterprise v19.2 detection strategies, analytics, log sources

T1048.003 Exfiltration Over Unencrypted Non-C2 Protocol secondary impact

Sigma rules tagged attack.t1048.003 (9)

T1053.005 Scheduled Task primary impact

Sigma rules tagged attack.t1053.005 (51)

T1136 Create Account secondary impact

Sigma rules tagged attack.t1136 (3)

T1190 Exploit Public-Facing Application exploitation technique

Sigma rules tagged attack.t1190 (149)

T1486 Data Encrypted for Impact secondary impact

Sigma rules tagged attack.t1486 (16)

Sigma rules tagged `attack.t1048.003` (9)

Sigma rules tagged `attack.t1053.005` (51)

Sigma rules tagged `attack.t1136` (3)

Sigma rules tagged `attack.t1190` (149)

Sigma rules tagged `attack.t1486` (16)