Detection Strategy for Weaken Encryption on Network Devices

Technique Detected:  Weaken Encryption | T1600

ID: DET0339
Domains: Enterprise
Analytics: AN0961
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN0961

Defenders may observe unauthorized modifications to encryption-related configuration files, firmware, or crypto modules on network devices. Suspicious patterns include changes to cipher suite configurations, unexpected firmware updates affecting crypto libraries, disabling of hardware cryptographic accelerators, or reductions in key length policies. Correlating configuration changes with anomalies in encrypted traffic characteristics (e.g., weaker ciphers or sudden plaintext transmission) strengthens detection.

Log Sources
Data Component Name Channel
File Modification (DC0061) networkdevice:config Configuration change events referencing encryption, TLS/SSL, or IPSec settings
Network Traffic Content (DC0085) NSM:Flow Traffic patterns showing downgrade from strong encryption (AES-256) to weaker or plaintext protocols
Module Load (DC0016) snmp:status Status change in cryptographic hardware modules (enabled -> disabled)
Mutable Elements
Field Description
CipherSuiteWhitelist List of approved encryption algorithms and key lengths; customizable to organizational policy.
TimeWindow Correlation period between configuration changes and abnormal traffic; adjustable to reduce false positives.
AuthorizedFirmwareSources Known trusted sources of firmware updates; deviations indicate possible compromise.
TrafficEntropyThreshold Baseline entropy measurements of encrypted traffic; deviations may reveal weakening of encryption.