Privesc Linux

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, the linpriv_enum.py methodology, 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_creds primer.
• 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 NFS no_root_squash.
• references/container-namespace-escape.md — runc Leaky Vessels CVE-2024-21626, Docker socket / privileged-container / --pid=host / CAP_SYS_PTRACE escapes, cgroup-v1 release_agent, user namespaces, and Kubernetes service-account-token → pod escape.