AN1570 Analytic 1570

Network Devices · attack.mitre.org · ATT&CK Enterprise v19.2

<p>Defenders may observe adversary attempts to downgrade system images by monitoring for anomalous file transfers of OS image files (via TFTP, FTP, SCP), configuration changes pointing boot system variables to older image files, unexpected OS version strings after reboot, and checksum mismatches against approved baseline images. Suspicious chains include transfer of an older image, alteration of boot configuration, and reboot/reload of the device. Adversaries may also tamper with CLI output to disguise downgrade attempts, requiring independent validation of OS version and integrity.</p>

Detects: T1601.002 Downgrade System Image
Part of: DET0569 Detection Strategy for Downgrade System Image on Network Devices

Log sources and channels

Exactly as MITRE states them in x_mitre_log_source_references. Where a channel is vague, it is vague in the source; kevmap does not tidy it.

Log source	Channel	Data component
networkdevice:cli	`Execution of commands such as 'copy tftp flash', 'boot system <image>', 'reload'`	DC0064 Command Execution
networkdevice:config	`Configuration changes referencing older image versions or unexpected boot parameters`	DC0061 File Modification
networkdevice:syslog	`OS version query results inconsistent with expected or approved version list`	DC0059 File Metadata

Mutable elements

Parameters MITRE marks as environment-specific. These are the knobs you are expected to tune; they are why an analytic is not a rule.

Field	Description
`ApprovedFirmwareVersions`	Whitelist of supported and validated OS versions for devices; helps reduce false positives.
`ChecksumBaseline`	Baseline cryptographic hashes of valid OS images; deviations indicate possible downgrade or tampering.
`TimeWindow`	Correlation period to detect the chain of file transfer → boot config change → reboot event.
`AuthorizedAdminAccounts`	Accounts authorized to perform OS upgrades/downgrades; anomalies suggest misuse or compromise.