Suspicious SUID Binary Execution
Description
Detects execution of SUID binaries that may be used for privilege escalation under the root effective user when the real user and parent user are not root, combined with minimal argument counts and suspicious parent context (interpreters, short shell -c invocations, or parents running from user-writable paths) to indicate potential misuse of SUID binaries for privilege escalation.
Query · eql
process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and (
(process.user.id == "0" and process.real_user.id != "0" and process.parent.user.id != "0") or
(process.group.id == "0" and process.real_group.id != "0" and process.parent.group.id != "0")
) and
(
(process.name in ("su", "passwd", "unix_chkpwd") and process.args_count <= 2) or
(
process.name in ("pkexec", "fusermount", "fusermount3", "mount", "umount", "newgrp", "chsh") and
process.args_count == 1
) or
process.name in (
"sudoedit", "gpasswd", "chfn", "polkit-agent-helper-1", "dbus-daemon-launch-helper", "ssh-keysign",
"pam_extrausers_chkpwd", "expiry", "chage", "crontab", "wall", "bsd-write", "ssh-agent",
"ping6", "traceroute", "mtr", "ntfs-3g", "Xorg.wrap", "chrome-sandbox", "bwrap"
)
) and
(
process.parent.name like (".*", "python*", "perl*", "ruby*", "lua*", "php*", "node", "deno", "bun", "java") or
process.parent.executable like ("./*", "/tmp/*", "/var/tmp/*", "/dev/shm/*", "/run/user/*", "/var/run/user/*", "/home/*/*") or
(
process.parent.name in ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish", "mksh") and
process.parent.args in ("-c", "-cl", "-lc", "--command", "-ic", "-ci", "-bash", "-sh", "-zsh", "-dash", "-fish", "-ksh", "-mksh") and
process.parent.args_count <= 4
)
) and
not (
(process.name == "crontab" and process.args in ("-l", "-e")) or
(process.name in ("passwd", "chsh") and process.args == "--version")
)
Known false positives
- Some automation or break-glass tooling may invoke SUID binaries from scripts under /home; validate parent identity and change tickets before escalating.
Analyst notes
Investigating Suspicious SUID Binary Execution
Confirm whether the non-root real user should be invoking SUID binaries as root. Review the parent process tree, script path, and any preceding download or decode activity.
Possible investigation steps
- Inspect
process.parent.command_lineand working directory for obfuscation or one-liners. - Check authentication and sudoers policy for the user.
- Pivot on the host for additional privilege escalation or persistence in the same session.
Response and remediation
- If unauthorized, contain the session, revoke elevated access, and review sudoers and polkit policy for tampering.