Log Enumeration

What the technique is

Adversaries may enumerate system and service logs to find useful data. These logs may highlight various types of valuable insights for an adversary, such as user authentication records (Account Discovery), security or vulnerable software (Software Discovery), or hosts within a compromised network (Remote System Discovery). Host binaries may be leveraged to collect system logs. Examples include using wevtutil.exe or PowerShell on Windows to access and/or export security event information. In cloud environments, adversaries may leverage utilities such as the Azure VM Agent’s CollectGuestLogs.exe to collect security logs from cloud hosted infrastructure. Adversaries may also target centralized logging infrastructure such as SIEMs. Logs may also be bulk exported and sent to adversary-controlled infrastructure for offline analysis. In addition to gaining a better understanding of the environment, adversaries may also monitor logs in real time to track incident response procedures. This may allow them to adjust their techniques in order to maintain persistence or evade defenses.

What MITRE says you would watch

• AN0705

  Monitor for use of native utilities such as wevtutil.exe or PowerShell cmdlets (Get-WinEvent, Get-EventLog) to enumerate or export logs. Unusual access to security or system event channels, especially by non-administrative users or processes, should be correlated with subsequent file export or network transfer activity.

• AN0706

  Monitor for suspicious use of commands such as cat, less, grep, or journalctl accessing /var/log/ files. Abnormal enumeration of authentication logs (auth.log, secure) or bulk access to multiple logs in short time windows should be flagged.

• AN0707

  Detect abnormal access to unified logs via log show or fs_usage targeting system log files. Monitor for execution of shell utilities (cat, grep) against /var/log/system.log and for plist modifications enabling verbose logging.