Linux Auth Log
Authentication and authorization events emitted by PAM-aware services — sshd logins, sudo invocations, su attempts, screen unlocks, and polkit decisions. The first place to look when scoping a Linux compromise.
Where to find it
Default filesystem paths and registry locations. Collect these with your preferred live-response or disk-image tooling.
- $/var/log/auth.log
- $/var/log/secure
- $/var/log/auth.log.1
- $/var/log/auth.log.*.gz
Forensic significance
Common scenarios in which this artifact becomes decisive evidence.
- SSH brute-force and password spray detection
- Mapping every sudo command to a real user and TTY
- Identifying lateral movement via accepted public-key authentications
- Detecting privilege abuse — sudo to root from non-admin accounts
MITRE ATT&CK mapping
Techniques this artifact can help detect or substantiate. Click a technique to view the official MITRE entry.
Tools that parse it
unJaena AI and other DFIR tools commonly used to extract evidence from this artifact.
Related artifacts
systemd Journal (journald)
Binary, structured, indexed log store written by systemd-journald. Contains kernel ring buffer, dmesg, all unit (service) output, and authenticated metadata such as UID, GID, PID, command line, and SELinux context for every entry.
Linux Syslog
Plain-text system event log written by rsyslog or syslog-ng, recording kernel messages, daemon output, cron jobs, and (on older distros) authentication events. Standard format on Debian/Ubuntu and RHEL/CentOS systems without journald-only logging.
Bash Shell History
Per-user record of every interactive shell command executed by Bash, written to ~/.bash_history on logout (or in real time when HISTTIMEFORMAT and PROMPT_COMMAND are configured).
RecentDocs
Explorer tracks recently opened files per extension in HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\RecentDocs, including files on removed storage.
References & further reading
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