IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Potential OpenSSH Backdoor Logging Activity
editPotential OpenSSH Backdoor Logging Activity
editIdentifies a Secure Shell (SSH) client or server process creating or writing to a known SSH backdoor log file. Adversaries may modify SSH related binaries for persistence or credential access via patching sensitive functions to enable unauthorized access or to log SSH credentials for exfiltration.
Rule type: eql
Rule indices:
- auditbeat-*
- logs-endpoint.events.*
Severity: high
Risk score: 73
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Linux
- Threat Detection
- Persistence
- Credential Access
Version: 2
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guide
edit## Config If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
Rule query
editfile where event.type == "change" and process.executable : ("/usr/sbin/sshd", "/usr/bin/ssh") and ( file.name : (".*", "~*") or file.extension : ("in", "out", "ini", "h", "gz", "so", "sock", "sync", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9") or file.path : ( "/private/etc/*--", "/usr/share/*", "/usr/include/*", "/usr/local/include/*", "/private/tmp/*", "/private/var/tmp/*", "/usr/tmp/*", "/usr/share/man/*", "/usr/local/share/*", "/usr/lib/*.so.*", "/private/etc/ssh/.sshd_auth", "/usr/bin/ssd", "/private/var/opt/power", "/private/etc/ssh/ssh_known_hosts", "/private/var/html/lol", "/private/var/log/utmp", "/private/var/lib", "/var/run/sshd/sshd.pid", "/var/run/nscd/ns.pid", "/var/run/udev/ud.pid", "/var/run/udevd.pid" ) )
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Credential Access
- ID: TA0006
- Reference URL: https://attack.mitre.org/tactics/TA0006/
-
Technique:
- Name: Modify Authentication Process
- ID: T1556
- Reference URL: https://attack.mitre.org/techniques/T1556/
-
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
-
Technique:
- Name: Compromise Client Software Binary
- ID: T1554
- Reference URL: https://attack.mitre.org/techniques/T1554/