3eeee01f06
10th module. Ubuntu-specific userns + overlayfs LPE that injects file
capabilities cross-namespace.
- modules/overlayfs_cve_2021_3493/iamroot_modules.{c,h}:
- is_ubuntu() — parses /etc/os-release for ID=ubuntu or
ID_LIKE=ubuntu. Non-Ubuntu hosts get IAMROOT_OK immediately (the
bug is specific to Ubuntu's modified overlayfs).
- unprivileged_userns_clone gate — sysctl=0 → PRECOND_FAIL
- Active probe (--active): forks a child that enters userns +
mountns and attempts the overlayfs mount inside /tmp. Mount
success on Ubuntu = VULNERABLE. Mount denied = patched / AppArmor
block. Child-isolated so parent's namespace state is untouched.
- Version fallback: kernel < 5.13 = vulnerable-by-inference for
Ubuntu kernels; recommend --active for confirmation.
- Exploit: detect-only stub. Reference vsh's exploit-cve-2021-3493
for full version (mount overlayfs in userns, drop binary with
cap_setuid+ep into upper layer, re-exec outside ns).
- Embedded auditd rules: mount(overlay) syscall + security.capability
xattr writes (the exploit's two-step footprint).
Verified end-to-end on kctf-mgr (Debian):
iamroot --scan → 'not Ubuntu — bug is Ubuntu-specific' → IAMROOT_OK
Module count: 10. Active-probe pattern now applies to dirty_pipe,
entrybleed, and overlayfs (and copy_fail_family via existing
dirtyfail_active_probes global). Detect quality across the corpus
materially improved this session.
6.6 KiB
6.6 KiB
CVE inventory
The curated list of CVEs IAMROOT exploits, with patch status and module status. Updated as new modules land or as upstream patches ship.
Status legend:
- 🟢 WORKING — module verified to land root on a vulnerable host
- 🟡 PARTIAL — module detects + exploits on some distros, not all
- 🔵 DETECT-ONLY — module fingerprints presence/absence but no exploit (yet). Useful for blue teams.
- ⚪ PLANNED — stub exists, work not started
- 🔴 DEPRECATED — fully patched everywhere relevant; kept for historical reference only
Inventory
| CVE | Name | Class | First patched | IAMROOT module | Status | Notes |
|---|---|---|---|---|---|---|
| CVE-2026-31431 | Copy Fail (algif_aead authencesn page-cache write) |
LPE (page-cache write → /etc/passwd) | mainline 2026-04-22 | copy_fail |
🟢 | Verified on Ubuntu 26.04, Alma 9, Debian 13. Full AppArmor bypass. |
| CVE-2026-43284 (v4) | Dirty Frag — IPv4 xfrm-ESP page-cache write | LPE (same primitive shape as Copy Fail, different trigger) | mainline 2026-05-XX | dirty_frag_esp |
🟢 | Full PoC + active-probe scan |
| CVE-2026-43284 (v6) | Dirty Frag — IPv6 xfrm-ESP (esp6) |
LPE | mainline 2026-05-XX | dirty_frag_esp6 |
🟢 | V6 STORE shift auto-calibrated per kernel build |
| CVE-2026-43500 | Dirty Frag — RxRPC page-cache write | LPE | mainline 2026-05-XX | dirty_frag_rxrpc |
🟢 | |
| (variant, no CVE) | Copy Fail GCM variant — xfrm-ESP rfc4106(gcm(aes)) page-cache write |
LPE | n/a | copy_fail_gcm |
🟢 | Sibling primitive, same fix |
| CVE-2022-0847 | Dirty Pipe — pipe PIPE_BUF_FLAG_CAN_MERGE write |
LPE (arbitrary file write into page cache) | mainline 5.17 (2022-02-23) | dirty_pipe |
🟢 | Full detect + exploit + cleanup. Detect: branch-backport ranges + active sentinel probe (--active fires the primitive against a /tmp probe file and verifies the page cache poisoning lands — catches silent distro backports the version check misses). Exploit: page-cache write into /etc/passwd UID field followed by su to drop a root shell. Auto-refuses on patched kernels. Cleanup: drop_caches + POSIX_FADV_DONTNEED. |
| CVE-2023-0458 | EntryBleed — KPTI prefetchnta KASLR bypass | INFO-LEAK (kbase) | mainline (partial mitigations only) | entrybleed |
🟢 | Stage-1 leak brick. Working on lts-6.12.86 (verified 2026-05-16 via iamroot --exploit entrybleed --i-know). Default entry_SYSCALL_64 slot offset matches lts-6.12.x; override via IAMROOT_ENTRYBLEED_OFFSET=0x.... Other modules can call entrybleed_leak_kbase_lib() as a library. x86_64 only. |
| CVE-2026-31402 | NFS replay-cache heap overflow | LPE (NFS server) | mainline 2026-04-03 | — | ⚪ | Candidate. Different audience (NFS servers) — TBD whether in-scope. |
| CVE-2021-4034 | Pwnkit — pkexec argv[0]=NULL → env-injection | LPE (userspace setuid binary) | polkit 0.121 (2022-01-25) | pwnkit |
🟢 | Full detect + exploit (canonical Qualys-style: gconv-modules + execve NULL-argv). Detect handles both polkit version formats (legacy "0.105" + modern "126"). Exploit compiles payload via target's gcc → falls back gracefully if no cc available. Cleanup nukes /tmp/iamroot-pwnkit-* workdirs. First userspace LPE in IAMROOT. Ships auditd + sigma rules. |
| CVE-2024-1086 | nf_tables — nft_verdict_init cross-cache UAF |
LPE (kernel arbitrary R/W via slab UAF) | mainline 6.8-rc1 (Jan 2024) | nf_tables |
🔵 | Detect-only. Branch-backport ranges checked (6.7.2 / 6.6.13 / 6.1.74 / 5.15.149 / 5.10.210 / 5.4.269). Also checks unprivileged user_ns clone availability (the exploit's trigger gate) — reports PRECOND_FAIL if userns is locked down even when the kernel is vulnerable. Full Notselwyn-style exploit is the next nf_tables commit. |
| CVE-2021-3493 | Ubuntu overlayfs userns file-capability injection | LPE (host root via file caps in userns-mounted overlayfs) | Ubuntu USN-4915-1 (Apr 2021) | overlayfs |
🔵 | Detect-only. Ubuntu-specific (vanilla upstream didn't enable userns-overlayfs-mount until 5.11). Detect: parses /etc/os-release for ID=ubuntu, checks unprivileged_userns_clone sysctl, AND with --active actually attempts the userns+overlayfs mount as a fork-isolated probe. Reports OK on non-Ubuntu, PRECOND_FAIL if userns locked down. Ships auditd rules covering mount(overlay) + setxattr(security.capability). |
| CVE-TBD | Fragnesia (ESP shared-frag in-place encrypt) | LPE (page-cache write) | mainline TBD | _stubs/fragnesia_TBD |
⚪ | Stub. Per findings/audit_leak_write_modprobe_backups_2026-05-16.md, requires CAP_NET_ADMIN in userns netns — may or may not be in-scope depending on target environment. |
Operations supported per module
Symbols: ✓ = supported, — = not applicable / no automated path.
| Module | --scan (detect) | --exploit | --mitigate | --cleanup | --detect-rules |
|---|---|---|---|---|---|
| copy_fail | ✓ | ✓ | ✓ (blacklist algif_aead + AA sysctl) | ✓ (revert mit or evict page cache) | ✓ (auditd + sigma) |
| copy_fail_gcm | ✓ | ✓ | ✓ (same family-wide) | ✓ | ✓ |
| dirty_frag_esp | ✓ | ✓ | ✓ (same family-wide) | ✓ | ✓ |
| dirty_frag_esp6 | ✓ | ✓ | ✓ (same family-wide) | ✓ | ✓ |
| dirty_frag_rxrpc | ✓ | ✓ | ✓ (same family-wide) | ✓ | ✓ |
| dirty_pipe | ✓ | ✓ | — (only fix is upgrade kernel) | ✓ (evict page cache) | ✓ (auditd + sigma) |
| entrybleed | ✓ | ✓ (leak kbase) | — (no canonical patch) | — | ✓ (sigma informational) |
Pipeline for additions
- Bug must be patched in upstream mainline (we don't bundle 0-days)
- Either CVE-assigned or has clear advisory/patch reference
- Affects a kernel version range with realistic deployment footprint (we don't bundle exploits for kernels nobody runs)
- PoC works on at least one distro+kernel in our CI matrix
- Detection signature(s) shipped alongside the exploit
Patch-status tracking
Each module's kernel-range.json (planned) declares the affected
range. CI verifies the exploit fails on the first-patched version
and succeeds below it. When a distro backports the fix into a kernel
version below the original first-patched, the matrix updates and
the relevant distro drops out of the "WORKING" list for that module.
Why we exclude some things
- 0-days the maintainer found themselves: those go through responsible disclosure first, then enter IAMROOT after upstream patch
- kCTF VRP submissions in flight: same as above; disclosure before bundling
- Hardware-specific side channels (Spectre/Meltdown variants): out of scope; not page-cache or process-isolation primitives
- Container-escape only: unless it cleanly chains to host-root, out of scope (separate tool space)