Detect LiteSpeed cPanel Plugin UNIX Symbolic Link (Symlink) Following Vulnerability in CrowdStrike LogScale
Detects exploitation of CVE-2026-54420, a UNIX symbolic link (symlink) following vulnerability in the LiteSpeed cPanel Plugin. Attackers with local access can create malicious symlinks to read or overwrite files outside the intended directory, potentially leading to privilege escalation or unauthorized file access on cPanel-managed hosting servers. This vulnerability is actively exploited in the wild (CISA KEV).
MITRE ATT&CK
LogScale Detection Query
#event_simpleName IN ("SyntheticProcessRollup2", "ProcessRollup2", "FileOpenInfo")
| ComputerName, UserName, FileName, CommandLine, FilePath
| CommandLine = /ln\s+(-s|--symbolic)/i
OR (FileName IN ("lsphp", "lshttpd", "litespeed", "lsup.sh") AND CommandLine = /symlink/i)
| eval litespeed_context = if(CommandLine = /(\/usr\/local\/lsws|\/var\/lsws|\/etc\/lsws|\/opt\/cpanel)/i OR FilePath = /(\/usr\/local\/lsws|\/var\/lsws)/i, "yes", "no")
| eval sensitive_target = if(CommandLine = /(\/etc\/passwd|\/etc\/shadow|\/root\/|\/etc\/ssh|\/etc\/sudoers)/i, "yes", "no")
| where litespeed_context = "yes" OR sensitive_target = "yes"
| table timestamp, ComputerName, UserName, FileName, CommandLine, litespeed_context, sensitive_target
| sort timestamp descCrowdStrike Falcon CQL query detecting process execution events where symlink commands are run in the context of LiteSpeed binaries or LiteSpeed filesystem paths, or where symlinks target sensitive operating system files.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate LiteSpeed cPanel plugin updates triggered by hosting administrators
- EasyApache 4 PHP extension management that creates symlinks under /opt/cpanel paths
- WHM automated update tasks that modify LiteSpeed web server configuration via symlinks
- Penetration testers operating in authorized cPanel lab environments
Other platforms for CVE-2026-54420
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Create Malicious Symlink in LiteSpeed Plugin Directory Targeting /etc/shadow
Expected signal: auditd SYSCALL=symlink with a1 pointing to /etc/shadow; FileOpenInfo event on /etc/shadow via the symlink path; process creating the symlink is a non-root user
- Test 2Symlink Traversal via LiteSpeed Binary Process Simulation
Expected signal: SYSCALL=symlink event for the ln -sv command; stat and readlink syscalls on the symlink; auditd logs should capture the effective UID and process name
- Test 3Enumerate LiteSpeed Plugin Directory and Create Targeted Symlink Chain
Expected signal: Multiple syscall events: find spawning openat calls on LiteSpeed paths; SYSCALL=symlink for the ln command; readdir on /root/.ssh via the symlink (if permitted); auditd AVC denials if SELinux/AppArmor active
References (4)
- https://blog.litespeedtech.com/2026/06/01/security-update-for-litespeed-cpanel-plugin-2/
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-54420
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