Detect LiteSpeed cPanel Plugin UNIX Symbolic Link (Symlink) Following Vulnerability in IBM QRadar
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
QRadar Detection Query
SELECT
DATEFORMAT(devicetime, 'yyyy-MM-dd HH:mm:ss') AS event_time,
sourceip,
username,
"HOST"(sourceip) AS hostname,
QIDNAME(qid) AS event_name,
"UTF8"(payload) AS raw_payload,
CATEGORYNAME(category) AS category
FROM events
WHERE LOGSOURCETYPENAME(devicetype) IN ('Linux OS', 'Syslog', 'IBM Security QRadar Log Source Extension')
AND (
("UTF8"(payload) ILIKE '%symlink%' OR "UTF8"(payload) ILIKE '%ln -s%' OR "UTF8"(payload) ILIKE '%symlinkat%')
AND (
"UTF8"(payload) ILIKE '%lsws%'
OR "UTF8"(payload) ILIKE '%lsphp%'
OR "UTF8"(payload) ILIKE '%litespeed%'
OR "UTF8"(payload) ILIKE '%cpanel-plugin%'
OR "UTF8"(payload) ILIKE '%/usr/local/lsws%'
)
)
OR (
("UTF8"(payload) ILIKE '%ln -s%' OR "UTF8"(payload) ILIKE '%symlinkat%')
AND (
"UTF8"(payload) ILIKE '%/etc/shadow%'
OR "UTF8"(payload) ILIKE '%/etc/passwd%'
OR "UTF8"(payload) ILIKE '%/etc/sudoers%'
OR "UTF8"(payload) ILIKE '%/root/%'
OR "UTF8"(payload) ILIKE '%/etc/ssh/%'
)
)
LAST 60 MINUTES
ORDER BY devicetime DESCData Sources
Required Tables
False Positives & Tuning
- LiteSpeed plugin installer scripts run by administrators performing legitimate upgrades
- cPanel update automation (upcp) that manages symlinks as part of software maintenance
- Imunify360 or similar cPanel security plugins performing filesystem integrity checks
- Developer testing environments where PHP binaries are symlinked for version management
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
Unlock Pro Content
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