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SKELETONKEY/ROADMAP.md
T
leviathan a8c8d5ef1f modules: add dirtydecrypt (CVE-2026-31635) + fragnesia (CVE-2026-46300)
Two new page-cache-write LPE modules, both ported from the public V12
security PoCs (github.com/v12-security/pocs):

- dirtydecrypt (CVE-2026-31635): rxgk missing-COW in-place decrypt.
  rxgk_decrypt_skb() decrypts spliced page-cache pages before the HMAC
  check, corrupting the page cache of a read-only file. Sibling of
  Copy Fail / Dirty Frag in the rxrpc subsystem.

- fragnesia (CVE-2026-46300): XFRM ESP-in-TCP skb_try_coalesce() loses
  the SHARED_FRAG marker, so the ESP-in-TCP receive path decrypts
  page-cache pages in place. A latent bug exposed by the Dirty Frag
  fix (f4c50a4034e6). Retires the old _stubs/fragnesia_TBD stub.

Both wrap the PoC exploit primitive in the skeletonkey_module
interface: detect/exploit/cleanup, an --active /tmp sentinel probe,
--no-shell support, and embedded auditd + sigma rules. The exploit
body runs in a forked child so the PoC's exit()/die() paths cannot
tear down the dispatcher. The fragnesia port drops the upstream PoC's
ANSI TUI (incompatible with a shared dispatcher); the exploit
mechanism is reproduced faithfully. Linux-only code is guarded with
#ifdef __linux__ so the modules still compile on non-Linux dev boxes.

VERIFICATION: ported, NOT yet validated end-to-end on a
vulnerable-kernel VM. The CVE fix commits are not pinned, so detect()
is precondition-only (PRECOND_FAIL / TEST_ERROR, never a blind
VULNERABLE) and --auto will not fire them unless --active confirms.
macOS stub-path compiles verified locally; the Linux exploit-path
build is covered by CI (build.yml, ubuntu) only. See each MODULE.md.

Wiring: core/registry.h, skeletonkey.c, Makefile, CVES.md, ROADMAP.md.
2026-05-22 18:22:30 -04:00

11 KiB
Raw Blame History

Roadmap

What's coming next, in priority order. Dates are aspirational, not commitments.

Phase 0 — Bootstrap (DONE as of 2026-05-16)

  • Repo structure (modules/, core/, docs/, tools/, tests/)
  • Absorbed DIRTYFAIL as the first module (modules/copy_fail_family/)
  • Top-level README, CVES.md, ROADMAP.md, docs/ARCHITECTURE.md, docs/ETHICS.md
  • LICENSE (MIT)
  • Private GitHub repo

Phase 1 — Make the bundling real (DONE 2026-05-16)

  • Top-level skeletonkey dispatcher CLI (skeletonkey.c) — module registry, route to module's detect/exploit
  • Module interface header (core/module.h) — standard skeletonkey_module struct + skeletonkey_result_t (numerically aligned with copy_fail_family's df_result_t for zero-cost bridging)
  • core/registry.{c,h} — flat-array registry with find_by_name
  • modules/copy_fail_family/skeletonkey_modules.{c,h} — bridge layer exposing 5 modules
  • Top-level Makefile that builds all modules into one binary
  • Smoke test: skeletonkey --scan --json produces ingest-ready JSON; skeletonkey --list prints the module inventory
  • Deferred to Phase 1.5: extract apparmor_bypass.c, exploit_su.c, common.c, fcrypt.c into core/ (shared across families). Phase 1 keeps them inside copy_fail_family/src/ because there's only one family today; the extraction is mechanical and lands when a second family arrives.

Phase 2 — Add Dirty Pipe (CVE-2022-0847) — PARTIAL (DETECT done 2026-05-16)

Public PoC, well-understood, useful for completeness — SKELETONKEY without Dirty Pipe is incomplete as a "historical bundle." Affects kernels ≤5.16.11/≤5.15.25/≤5.10.102 so coverage is older deployments (worth bundling — many production boxes still run these).

  • modules/dirty_pipe_cve_2022_0847/ directory promoted out of _stubs/
  • core/kernel_range.{c,h} — branch-aware patched-version comparison (reusable by every future module)
  • dirty_pipe_detect() — kernel version check against branch-backport thresholds (5.10.102 / 5.15.25 / 5.16.11 / 5.17+)
  • Detection rules: auditd.rules (splice() syscall + passwd/shadow watches) and sigma.yml (non-root modification of sensitive files)
  • Registered in skeletonkey --list / --scan output. Verified on kernel 6.12.86 → correctly reports OK (patched).
  • Phase 2 complete (2026-05-16): full exploit landed. Inline passwd-UID and page-cache-revert helpers in the module (~80 lines). Extraction into core/host is Phase 1.5 work — deferred until a third module needs the same helpers. (Two-of-two duplication is acceptable; three-of-three triggers extraction.)
  • Exploit refuses to fire when detect() reports patched (verified end-to-end on kernel 6.12.86 — refuses cleanly).
  • Cleanup function (dirty_pipe --cleanup) added: evicts /etc/passwd via POSIX_FADV_DONTNEED + drop_caches.
  • CI matrix: Ubuntu 20.04 with kernel 5.13 (vulnerable), Debian 11 with 5.10.0-8 (vulnerable), Debian 13 with 6.12.x (patched — should detect as OK). Phase 4 work.

Phase 3 — EntryBleed (CVE-2023-0458) as stage-1 leak brick (DONE 2026-05-16)

EntryBleed is not a standalone LPE. It's a kbase leak primitive that other modules can chain. Bundled because:

  • Stage-1 of any future "build-your-own LPE" workflow

  • Detection rules for KPTI side-channel attempts are useful for defenders

  • Already works empirically on lts-6.12.88 (verified 2026-05-16)

  • modules/entrybleed_cve_2023_0458/ — leak primitive + detect

  • Exposed as a library helper: other modules can call entrybleed_leak_kbase_lib() (declared in skeletonkey_modules.h)

  • Wired into skeletonkey.c registry; skeletonkey --exploit entrybleed --i-know produces a kbase leak. Verified on kctf-mgr: leaked 0xffffffff8d800000 with KASLR slide 0xc800000.

  • entry_SYSCALL_64 slot offset configurable via SKELETONKEY_ENTRYBLEED_OFFSET env var (default matches lts-6.12.x). Future enhancement: auto-detect via /boot/System.map or /proc/kallsyms if accessible.

Phase 4 — CI matrix (PARTIAL — build-check landed 2026-05-16)

  • .github/workflows/build.yml: matrix of {gcc, clang} × {default, debug} builds on every push and PR. Includes smoke tests: --version, --list, --scan, --detect-rules in both auditd and sigma formats. Build failure breaks the merge gate. Static-build job runs continue-on-error (glibc + NSS issue; revisit with musl-gcc).
  • Distro+kernel VM matrix in GitHub Actions (Ubuntu 20.04 / 22.04 / 24.04 / 26.04, Debian 11 / 12 / 13, Alma 8 / 9 / 10, Fedora 39 / 40 / 41). Needs self-hosted runners or paid VM service; placeholder commented in build.yml.
  • Each module's exploit runs against matched-vulnerable VMs and MUST land root; runs against patched VMs and MUST fail at detect step
  • Nightly run; failures open issues automatically

Phase 5 — Detection signature export (DONE 2026-05-16)

  • skeletonkey --detect-rules --format=auditd — embedded auditd rules across all modules (deduped — family-shared rules emit once)
  • skeletonkey --detect-rules --format=sigma — embedded Sigma rules
  • --format=yara and --format=falco flags accepted; per-module strings can be added when authors ship them. Currently no module ships YARA or Falco rules (skipped cleanly).
  • struct skeletonkey_module gained detect_auditd, detect_sigma, detect_yara, detect_falco fields — each NULL or pointer to embedded C string. Self-contained binary, no data-dir install needed.
  • Sample SOC playbook in docs/DETECTION_PLAYBOOK.md — followup

Phase 6 — Mitigation mode (PARTIAL — copy_fail_family bridged 2026-05-16)

  • copy_fail_family: skeletonkey --mitigate copy_fail (or any family member) blacklists algif_aead + esp4 + esp6 + rxrpc, sets kernel.apparmor_restrict_unprivileged_userns=1, drops page cache. Bridged from existing DIRTYFAIL mitigate_apply().
  • copy_fail_family: skeletonkey --cleanup <name> routes by visible state: if /etc/modprobe.d/dirtyfail-mitigations.conf exists → mitigate_revert(); else evict /etc/passwd page cache. Heuristic sufficient for common usage patterns.
  • dirty_pipe: skeletonkey --cleanup dirty_pipe evicts /etc/passwd (already landed in Phase 2 complete).
  • dirty_pipe --mitigate: only real fix is "upgrade your kernel"; no automated mitigation possible. Document and skip.
  • entrybleed --mitigate: same — no canonical patch; document.
  • Idempotent re-run safety: copy_fail_family's apply is already idempotent (overwrites conf files). Re-verify per module.

Phase 7+ — More modules (started 2026-05-16, v0.1.0 cut 2026-05-16)

Backfill of historical and recent LPEs as time allows.

Landed in v0.1.0:

  • CVE-2016-5195 — Dirty COW: 🟢 FULL Phil-Oester-style race.
  • CVE-2017-7308 — AF_PACKET TPACKET_V3: 🟡 PRIMITIVE (overflow + skb spray + cred-race attempt, no portable cred R/W).
  • CVE-2019-13272 — PTRACE_TRACEME: 🟢 FULL jannh-style chain.
  • CVE-2020-14386 — AF_PACKET tp_reserve: 🟡 PRIMITIVE-DEMO.
  • CVE-2021-3493 — Ubuntu overlayfs userns: 🟢 FULL vsh-style.
  • CVE-2021-4034 — Pwnkit: 🟢 FULL Qualys-style.
  • CVE-2021-22555 — xt_compat heap-OOB: 🟡 PRIMITIVE (trigger + msg_msg cross-cache groom + MSG_COPY witness, no modprobe_path overwrite).
  • CVE-2022-0185 — fsconfig 4k OOB: 🟡 PRIMITIVE (trigger + cross-cache groom + neighbour-detect, no MSG_COPY arb-read finisher).
  • CVE-2022-0492 — cgroup_release_agent: 🟢 FULL universal structural exploit (no offsets, no race).
  • CVE-2022-2588 — cls_route4 dangling UAF: 🟡 PRIMITIVE (tc/ip add+rm + msg_msg spray + classify drive, no cred chain).
  • CVE-2023-0386 — overlayfs setuid copy-up: 🟢 FULL distro-agnostic.
  • CVE-2023-3269 — StackRot: 🟡 PRIMITIVE/RACE (driver + groom; ~<1% race-win per run, honest in module header).
  • CVE-2024-1086 — nf_tables verdict UAF: 🟡 PRIMITIVE (hand-rolled nfnetlink, NFT_GOTO+DROP malformed verdict, msg_msg kmalloc-cg-96 groom, no pipapo R/W chain).

Landed (ported from public PoC, pending VM verification):

  • CVE-2026-46300 — Fragnesia: 🟡 XFRM ESP-in-TCP page-cache write. Ported from the V12 PoC; the old _stubs/fragnesia_TBD stub is retired. The stub's open question ("is the unprivileged-userns-netns scenario in scope?") is resolved — the module ships and reports PRECOND_FAIL when the userns gate is closed.
  • CVE-2026-31635 — DirtyDecrypt: 🟡 rxgk missing-COW in-place decrypt page-cache write. Ported from the V12 PoC.
  • Verify both on a vulnerable-kernel VM, pin the CVE fix commits, add kernel_range tables, and promote 🟡🟢. Until then detect() is precondition-only (no version verdict) and --auto will not fire them blind.

Carry-overs:

  • CVE-2023-2008 — vmwgfx OOB write
  • CVE-2026-41651 — Pack2TheRoot (PackageKit daemon userspace LPE; cross-distro). Candidate — userspace LPE in the pwnkit vein.
  • Anything we ourselves disclose — bundled AFTER upstream patch ships (responsible-disclosure-first)

Phase 8 — Full-chain promotions (post v0.1.0)

The 7 🟡 PRIMITIVE modules each stop one or two steps short of full cred-overwrite. Promotion to 🟢 means landing the leak → R/W → modprobe_path-or-cred-rewrite stage on at least one tracked kernel. None requires fresh research — each has a public reference exploit; the work is porting the per-kernel offset dance into a portable shape compatible with SKELETONKEY's "no-fabricated-offsets" rule (most likely as an env-var override table per distro+kernel, with offset auto-resolve via System.map / kallsyms when accessible).

Priority order: nf_tables (Notselwyn pipapo R/W), netfilter_xtcompat (Andy Nguyen modprobe_path), af_packet (xairy sk_buff cred chase). The other four are lower priority — fuse_legacy and cls_route4 have narrower distro reach; af_packet2 piggybacks on af_packet; stackrot's race window makes it inherently low-yield.

Non-goals

  • No 0-day shipment. Everything in SKELETONKEY is post-patch.
  • No automated mass-targeting. No host-list mode. No automatic pivoting.
  • No persistence beyond --exploit-backdoor's /etc/passwd overwrite, which is overt and easily detected by any auditd rule we ship ourselves. Persistence-as-evasion is out of scope.
  • No container-runtime escapes unless they cleanly chain to host-root.
  • No Windows / macOS / non-Linux targets. Focus is the moat.