Encrypted Channel T1573
Tactic: Command & Control
Adversaries may employ an encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Despite the use of a secure algorithm, these implementations may be vulnerable to reverse engineering if secret keys are encoded and/or generated within malware samples/configuration files.
Events covered
5 catalog events are tagged with this technique by at least one rule.
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Sysmon | Event ID 3 | Network connection |
| Sysmon | Event ID 22 | DNSEvent (DNS query) |
| Security-Auditing | Event ID 4688 | A new process has been created. |
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Authoring guide
These 29 rules share fields, values, and exclusions.
Fields filtered most (67 distinct)
These fields appear most often in rule filters.
Top indicator values (181 distinct)
These values appear most often in rule predicates.
Exclusions (87 distinct)
These values appear most often in top-level exclusions.
Rules under this technique
These vendors publish rules tagged with this technique.
Sigma 6 rules
- Activity from Anonymous IP Addresses
- Activity from Infrequent Country
- Activity from Suspicious IP Addresses
- Kalambur Backdoor Curl TOR SOCKS Proxy Execution
- Potential Pikabot C2 Activity
- Suspicious SSL Connection
Elastic 8 rules
- Connection to Commonly Abused Free SSL Certificate Providers
- Default Cobalt Strike Team Server Certificate
- Deprecated TLS Version or Weak Cipher Negotiated Externally
- Newly Observed IPSEC NAT Traversal Peer
- Openssl Client or Server Activity
- Potential Command and Control via Windows Scripts
- Potential Self-Signed TLS Certificate Recently Issued on External Connection
- Suspicious Execution from a Windows Script
Splunk 7 rules
- Cisco Secure Firewall - Blacklisted SSL Certificate Fingerprint
- Cisco Secure Firewall - High EVE Threat Confidence
- Cisco Secure Firewall - Intrusion Events by Threat Activity
- Cisco Secure Firewall - Lumma Stealer Download Attempt
- Cisco Secure Firewall - Lumma Stealer Outbound Connection Attempt
- SSL Certificates with Punycode
- Zeek x509 Certificate with Punycode
Kusto 6 rules
- Cisco Cloud Security - Connection to non-corporate private network
- Detect DNS queries reporting multiple errors from different clients - Anomaly Based (ASIM DNS Solution)
- Detect DNS queries reporting multiple errors from different clients - Static threshold based (ASIM DNS Solution)
- Powershell Empire Cmdlets Executed in Command Line
- ProofpointPOD - Weak ciphers
- Ubiquiti - Unusual traffic