Techniques › T1600.001 › AN0681
AN0681 Analytic 0681
Network Devices · attack.mitre.org · ATT&CK Enterprise v19.2
<p>Defenders may observe attempts to alter cryptographic settings on network devices that reduce key strength or allowable cipher suites. Suspicious indicators include configuration changes that downgrade encryption algorithms, key length parameters, or the disabling of strong encryption in favor of legacy ciphers. These activities often appear as CLI commands modifying crypto policies, firmware changes affecting crypto libraries, or unexpected updates to key management files. Correlation across device config logs and traffic analysis showing weaker ciphers provides higher confidence of malicious key space reduction.</p>
- Detects
- T1600.001 Reduce Key Space
- Part of
- DET0243 Detection Strategy for Weaken Encryption: Reduce Key Space 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:config | Configuration changes referencing 'crypto', 'key length', 'cipher', or downgrade of encryption settings | DC0061 File Modification |
| networkdevice:cli | Execution of CLI commands altering crypto parameters (e.g., 'crypto key generate rsa modulus 512') | DC0064 Command Execution |
| NSM:Flow | Observed downgrade in negotiated cipher suites or TLS/SSH versions across sessions | DC0085 Network Traffic Content |
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 |
|---|---|
AllowedKeyLengths | Defines the minimum acceptable encryption key sizes; tunable to organizational policy. |
CipherSuiteBaseline | Baseline list of approved cipher suites for network sessions; deviations may indicate tampering. |
AuthorizedAdminAccounts | Whitelisted accounts for executing crypto configuration changes; ensures alerts only trigger on unauthorized actions. |
TimeWindow | Time correlation period between configuration change and anomalous traffic downgrade; adjustable to reduce noise. |