majiayu000 Linux Privilege Escalation
When to Activate
- Gained an initial unprivileged shell on a Linux host and need root or a higher-privileged account
- Post-exploitation lateral/vertical movement on Linux servers, workstations, CI runners, or appliances
- Container / Kubernetes pod foothold that needs to escape to the host node
- Triaging a host for misconfig-based LPE (SUID, sudo, capabilities, writable units/cron) before reaching for kernel 0-day
- CTF / lab challenges requiring privilege escalation with a defensible, detection-aware methodology
Technique Map
| Technique | ATT&CK | CWE | Reference | Script |
|---|---|---|---|---|
| Automated + manual enumeration (LinPEAS/pspy/LES2) | T1082, T1057 | CWE-200 | references/enumeration-tooling.md | scripts/linpriv_enum.py |
| Detection-aware / low-noise enumeration | T1082 | CWE-200 | references/enumeration-tooling.md | scripts/linpriv_enum.py |
| SUID/SGID binary abuse (GTFOBins) | T1548.001 | CWE-269 | references/suid-sudo-capabilities.md | scripts/cap_suid_hunter.sh |
| sudo misconfig + GTFOBins escape | T1548.003 | CWE-269 | references/suid-sudo-capabilities.md | scripts/cap_suid_hunter.sh |
| sudo host option LPE (CVE-2025-32462) | T1548.003 | CWE-863 | references/suid-sudo-capabilities.md | scripts/sudo_cve_2025_check.sh |
| sudo chroot/NSS LPE (CVE-2025-32463) | T1548.003 | CWE-829 | references/suid-sudo-capabilities.md | scripts/sudo_cve_2025_check.sh |
| Linux capabilities abuse (setuid/dac_read/sys_admin) | T1548 | CWE-250 | references/suid-sudo-capabilities.md | scripts/cap_suid_hunter.sh |
| LD_PRELOAD / LD_LIBRARY_PATH sudo hijack | T1574.006 | CWE-426 | references/suid-sudo-capabilities.md | scripts/cap_suid_hunter.sh |
| nf_tables double-free LPE (CVE-2024-1086) | T1068 | CWE-416 | references/kernel-exploits.md | scripts/kernel_exploit_suggester.py |
| io_uring memory-sharing LPE (CVE-2024-0582/2025-21836) | T1068 | CWE-416 | references/kernel-exploits.md | scripts/kernel_exploit_suggester.py |
| Dirty Pipe page-cache overwrite (CVE-2022-0847) | T1068 | CWE-787 | references/kernel-exploits.md | scripts/kernel_exploit_suggester.py |
| GameOver(lay) OverlayFS (CVE-2023-2640/32629) | T1068 | CWE-269 | references/kernel-exploits.md | scripts/kernel_exploit_suggester.py |
| udisks/libblockdev loop-mount LPE (CVE-2025-6019) | T1068 | CWE-250 | references/service-misconfig-lpe.md | scripts/linpriv_enum.py |
| PAM allow_active bypass (CVE-2025-6018) | T1068 | CWE-863 | references/service-misconfig-lpe.md | scripts/linpriv_enum.py |
| glibc ld.so Looney Tunables (CVE-2023-4911) | T1068 | CWE-787 | references/service-misconfig-lpe.md | scripts/kernel_exploit_suggester.py |
| polkit pkexec PwnKit (CVE-2021-4034) | T1548.001 | CWE-787 | references/service-misconfig-lpe.md | scripts/linpriv_enum.py |
| Cron/systemd/PATH/writable-file abuse | T1053.003, T1574.007 | CWE-732 | references/service-misconfig-lpe.md | scripts/linpriv_enum.py |
| NFS no_root_squash SUID drop | T1222.002 | CWE-732 | references/service-misconfig-lpe.md | scripts/linpriv_enum.py |
| runc fd-leak container escape (CVE-2024-21626) | T1611 | CWE-668 | references/container-namespace-escape.md | scripts/container_escape_check.sh |
| Docker socket / privileged container escape | T1611, T1610 | CWE-269 | references/container-namespace-escape.md | scripts/container_escape_check.sh |
| cgroup release_agent / CAP_SYS_ADMIN escape | T1611 | CWE-269 | references/container-namespace-escape.md | scripts/container_escape_check.sh |
| Kubernetes pod/token escape | T1611 | CWE-668 | references/container-namespace-escape.md | scripts/container_escape_check.sh |
Quick Start
# 0. Stabilize shell + baseline context
python3 -c 'import pty;pty.spawn("/bin/bash")'; export TERM=xterm
id; uname -a; cat /etc/os-release
# 1. Fast, detection-aware enumeration (custom, no external download needed)
python3 linpriv_enum.py --quick # quick wins triage
python3 linpriv_enum.py --full --json out.json # full sweep -> JSON evidence
# 2. SUID / capabilities / sudo triage (maps directly to GTFOBins)
./cap_suid_hunter.sh # ranks exploitable SUID + caps + sudo -l
# 3. sudo 2025 LPE check (no creds needed; default-config killers)
./sudo_cve_2025_check.sh # tests CVE-2025-32462 / -32463 + PwnKit
# 4. Kernel + glibc CVE mapping for current host
python3 kernel_exploit_suggester.py # uname/glibc/distro -> ranked modern LPEs
# 5. If containerized, check escape surface
./container_escape_check.sh # runc fd-leak, docker.sock, caps, k8s token
# 6. Validate root, then drop SUID backup or stable persistence per ROE
id; cp /bin/bash /tmp/.b && chmod 4755 /tmp/.b # only if authorized
OPSEC & Detection (summary)
| Technique | Telemetry / IOC | Detection (Sigma/EDR) | OPSEC note |
|---|---|---|---|
| LinPEAS / mass enum | Burst of find / -perm, hundreds of reads, which/getcap spam |
auditd execve of linpeas; EDR file-scan anomaly |
Prefer targeted enum (linpriv_enum.py --quick); avoid full FS walks on EDR hosts |
| SUID/GTFOBins escape | setuid() to 0 from non-root parent, shell with -p |
auditd uid-change without login; Falco Run shell untrusted |
Use the least-noisy binary; many GTFOBins one-liners are flagged by name |
| sudo CVE-2025-32463 | syslog sudo ... CHROOT=, NSS libnss_*.so from world-writable path |
Elastic "Potential CVE-2025-32463 Sudo Chroot Execution"; auditd -R usage |
chroot dir + fake nsswitch.conf are durable IOCs — clean the tree |
| sudo CVE-2025-32462 | sudo log with -h/HOST mismatch vs real hostname |
auditd sudo with --host not paired with -l |
leaves clean sudo log entry; blends with normal sudo |
| nf_tables CVE-2024-1086 | unshare/CLONE_NEWUSER + nftables from non-root; dmesg slab/UAF |
Falco Unprivileged Delegation of Page Faults; auditd unshare+nft |
namespace creation is logged; disable userns to neutralize |
| io_uring LPE | io_uring_setup syscall from unexpected proc |
auditd syscall=io_uring_setup; eBPF LSM | many distros now ship io_uring_disabled=2 |
| Looney Tunables CVE-2023-4911 | setuid exec with GLIBC_TUNABLES= containing =; core dumps |
Elastic "Potential Privilege Escalation via CVE-2023-4911" | env var is recorded in auditd execve; unset before exec where possible |
| udisks CVE-2025-6019 | D-Bus Filesystem.Resize/Check, loop mount in /tmp w/o nosuid |
auditd mount w/o nosuid; Falco mount-from-loop |
leaves loop device + XFS image; detach + shred image |
| pkexec PwnKit | pkexec with argc==0, GCONV_PATH= env, /var/... GConv module |
auditd pkexec + empty argv; Sigma proc_creation_lnx_pkexec |
dropped GConv .so + dir are IOCs; remove them |
| Container escape (runc) | /proc/self/fd/* cwd, host paths from container, runc exec anomalies |
Falco Container escape/Mount launched in container; CrowdStrike CWP |
escapes are heavily monitored in CWP — confirm scope before running |
| cron/PATH/writable unit | new file in /etc/cron*, systemctl daemon-reload, PATH-prepended bin |
auditd watch on /etc/cron*,/etc/systemd/*; Sigma cron tamper |
revert file mtimes / remove dropped scripts post-exploit |
Detailed Sigma rules, auditd rule snippets and IOC lists live inside each reference file's Detection subsection.
Deep Dives
references/enumeration-tooling.md— LinPEAS/pspy/LES2/unix-privesc-check, thelinpriv_enum.pymethodology, quick-win checklists, and low-noise enumeration for EDR-monitored hosts.references/suid-sudo-capabilities.md— SUID/SGID + GTFOBins, sudo misconfig escapes, sudo CVE-2025-32462 (host) and CVE-2025-32463 (chroot/NSS), Linux capabilities (cap_setuid/cap_dac_read_search/cap_sys_admin), and LD_PRELOAD/LD_LIBRARY_PATH sudo hijacking.references/kernel-exploits.md— nf_tables CVE-2024-1086 (and 2026 nftables UAFs), io_uring CVE-2024-0582 / CVE-2025-21836, Dirty Pipe CVE-2022-0847, GameOver(lay) CVE-2023-2640, plus a kernel-CVE selection methodology and ROP/commit_credsprimer.references/service-misconfig-lpe.md— udisks/libblockdev CVE-2025-6018/6019 chain, Looney Tunables CVE-2023-4911, PwnKit CVE-2021-4034, polkit/D-Bus abuse, cron/systemd/PATH hijacking, writable/etc/passwd, and NFSno_root_squash.references/container-namespace-escape.md— runc Leaky Vessels CVE-2024-21626, Docker socket / privileged-container /--pid=host/CAP_SYS_PTRACEescapes, cgroup-v1release_agent, user namespaces, and Kubernetes service-account-token → pod escape.