SKELETONKEY/docs/RELEASE_NOTES.md

SKELETONKEY v0.9.1 — VM verification sweep (22 → 27)

Five more CVEs empirically confirmed end-to-end against real Linux VMs via tools/verify-vm/:

CVE	Module	Target environment
CVE-2019-14287	sudo_runas_neg1	Ubuntu 18.04 (sudo 1.8.21p2 + (ALL,!root) grant via provisioner)
CVE-2020-29661	tioscpgrp	Ubuntu 20.04 pinned to 5.4.0-26 (genuinely below the 5.4.85 backport)
CVE-2024-26581	nft_pipapo	Ubuntu 22.04 + mainline 5.15.5 (below the 5.15.149 fix)
CVE-2025-32463	sudo_chwoot	Ubuntu 22.04 + sudo 1.9.16p1 built from upstream into /usr/local/bin
CVE-2025-6019	udisks_libblockdev	Debian 12 + udisks2 2.9.4 + polkit allow rule for the verifier user

Footer goes from 22 empirically verified → 27 empirically verified.

Verifier infrastructure (the why)

These verifications required real plumbing work that didn't exist before:

• Per-module provisioner hook (tools/verify-vm/provisioners/<module>.sh) — per-target setup that doesn't belong in the Vagrantfile (build sudo from source, install udisks2 + polkit rule, drop a sudoers grant) now lives in checked-in scripts that re-run idempotently on every verify.
• Two-phase provisioning in verify.sh — prep provisioners run first (install kernel, set grub default, drop polkit rule), then a conditional reboot if uname -r doesn't match the target, then the verifier proper. Fixes the silent-fail where the new kernel was installed but the VM never actually rebooted into it.
• GRUB_DEFAULT pin in both pin-kernel and pin-mainline blocks — without this, grub's debian-version-compare picks the highest-sorting vmlinuz as default; for downgrades (stock 4.15 → mainline 4.14.70, or stock 5.4.0-169 → pinned 5.4.0-26) the wrong kernel won boot.
• Old-mainline URL fallback — kernel.ubuntu.com puts ≤ 4.15 mainline debs at /v${KVER}/ not /v${KVER}/amd64/. Fallback handles both.

Honest residuals — 7 of 34 still unverified

Module	Why not verified
vmwgfx	needs a VMware guest; we're on Parallels
dirty_cow	needs ≤ 4.4 kernel — older than any supported Vagrant box
mutagen_astronomy	mainline 4.14.70 kernel-panics on Ubuntu 18.04 rootfs (Failed to execute /init (error -8) — kernel config mismatch). Genuinely needs CentOS 6 / Debian 7.
pintheft	needs RDS kernel module loaded (Arch only autoloads it)
vsock_uaf	needs vsock_loopback loaded — not autoloaded on common Vagrant boxes
dirtydecrypt, fragnesia	need Linux 7.0 — not yet shipping as any distro kernel

All seven are flagged in tools/verify-vm/targets.yaml with manual: true and a rationale.

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SKELETONKEY v0.9.0 — every year 2016 → 2026 now covered

Five gap-filling modules. Closes the 2018 hole entirely and thickens 2019 / 2020 / 2024.

CVE-2018-14634 — mutagen_astronomy (Qualys)

Closes the 2018 gap. create_elf_tables() int-wrap → on x86_64, a multi-GiB argv blob makes the kernel under-allocate the SUID carrier's stack and corrupt adjacent allocations. CISA-KEV-listed Jan 2026 despite the bug's age — legacy RHEL 7 / CentOS 7 / Debian 8 fleets still affected. 🟡 PRIMITIVE (trigger documented; Qualys' full chain not bundled per verified-vs-claimed). arch_support: x86_64+unverified-arm64.

CVE-2019-14287 — sudo_runas_neg1 (Joe Vennix)

sudo -u#-1 <cmd> → uid_t underflows to 0xFFFFFFFF → sudo treats it as uid 0 → runs <cmd> as root even when sudoers explicitly says "ALL except root". Pure userspace logic bug; the famous Apple Information Security finding. detect() looks for a (ALL,!root) grant in sudo -ln output. arch_support: any. Sudo < 1.8.28.

CVE-2020-29661 — tioscpgrp (Jann Horn / Project Zero)

TTY TIOCSPGRP ioctl race on PTY pairs → struct pid UAF in kmalloc-256. Affects everything through Linux 5.9.13. 🟡 PRIMITIVE (race-driver + msg_msg groom). Public PoCs from grsecurity/spender

• Maxime Peterlin. arch_support: x86_64+unverified-arm64.

CVE-2024-50264 — vsock_uaf (a13xp0p0v / Pwnie 2025 winner)

AF_VSOCK connect() races a POSIX signal that tears down the virtio_vsock_sock → UAF in kmalloc-96. Pwn2Own 2024 + Pwnie Award 2025 winner. Reachable as plain unprivileged user (no userns required — unusual). Two public exploit paths: @v4bel + @qwerty kernelCTF chain (BPF JIT spray + SLUBStick) and Alexander Popov's msg_msg path (PT SWARM Sep 2025). 🟡 PRIMITIVE. arch_support: x86_64+unverified-arm64.

CVE-2024-26581 — nft_pipapo (Notselwyn II, "Flipping Pages")

nft_set_pipapo destroy-race UAF. Sibling to our nf_tables module (CVE-2024-1086) — same Notselwyn "Flipping Pages" research paper, different specific bug in the pipapo set substrate. Same family detect signature. 🟡 PRIMITIVE. arch_support: x86_64+unverified-arm64.

Year-by-year coverage matrix

2016: ▓ 1     2021: ▓▓▓▓▓ 5     2025: ▓▓ 2
2017: ▓ 1     2022: ▓▓▓▓▓ 5     2026: ▓▓▓▓ 4
2018: ▓ 1 ←   2023: ▓▓▓▓▓▓▓▓ 8
2019: ▓▓ 2 ←  2024: ▓▓▓ 3 ←
2020: ▓▓ 2 ←

Every year 2016 → 2026 is now ≥1.

Corpus growth

	v0.8.0	v0.9.0
Modules registered	34	39
Distinct CVEs	29	34
Years with ≥1 CVE	10 of 11 (missing 2018)	11 of 11
Detection rules embedded	131	151
Arch-independent (any)	6	7
VM-verified	22	22

Other changes

• All 5 new modules ship complete detection-rule corpus (auditd + sigma + yara + falco) — corpus stays at 4-format parity with the rest of the modules.
• tools/refresh-cve-metadata.py runs against 34 CVEs (was 29); takes ~4 minutes due to NVD anonymous rate limit.

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SKELETONKEY v0.8.0 — 3 new 2025/2026 CVEs

Closes the 2025 coverage gap. Three new modules from CVEs disclosed 2025–2026, all with public PoC code we ported into proper SKELETONKEY modules:

CVE-2025-32463 — sudo_chwoot (Stratascale)

Critical (CVSS 9.3) sudo logic bug: sudo --chroot=<DIR> chroots into a user-controlled directory before completing authorization + resolves user/group via NSS inside the chroot. Plant a malicious libnss_*.so + an nsswitch.conf that points to it; sudo dlopens the .so as root, ctor fires, root shell. Affects sudo 1.9.14 to 1.9.17p0; fixed in 1.9.17p1 (which deprecated --chroot entirely). arch_support: any (pure userspace).

CVE-2025-6019 — udisks_libblockdev (Qualys)

udisks2 + libblockdev SUID-on-mount chain. libblockdev's internal filesystem-resize/repair mount path omits MS_NOSUID and MS_NODEV. udisks2 gates the operation on polkit's org.freedesktop.UDisks2.modify-device action, which is allow_active=yes by default → any active console session user can trigger it without a password. Build an ext4 image with a SUID-root shell inside, get udisks to mount it, execute the SUID shell. Affects libblockdev < 3.3.1, udisks2 < 2.10.2. arch_support: any.

CVE-2026-43494 — pintheft (V12 Security)

Linux kernel RDS zerocopy double-free. rds_message_zcopy_from_user() pins user pages one at a time; if a later page faults, the error unwind drops the already-pinned pages, but the msg's scatterlist cleanup drops them AGAIN. Each failed sendmsg(MSG_ZEROCOPY) leaks one pin refcount. Chain via io_uring fixed buffers to overwrite the page cache of a readable SUID binary → execve → root. Mainline fix commit 0cebaccef3ac (posted to netdev 2026-05-05). Among common distros only Arch Linux autoloads the rds module — Ubuntu / Debian / Fedora / RHEL / Alma / Rocky / Oracle Linux either don't build it or blacklist autoload. detect() correctly returns OK on non-Arch hosts (RDS unreachable from userland). 🟡 PRIMITIVE status: primitive fires; full cred-overwrite via the shared modprobe_path finisher requires --full-chain on x86_64.

Corpus growth

	v0.7.1	v0.8.0
Modules registered	31	34
Distinct CVEs	26	29
2025-CVE coverage	0	2
Detection rules embedded	119	131
Arch-independent (any)	4	6
CISA KEV-listed	10	10 (new ones not yet KEV'd)
VM-verified	22	22

Other changes

• tools/refresh-cve-metadata.py — added curl fallback for the CISA KEV CSV fetch (Python's urlopen was hitting timeouts against CISA's HTTP/2 endpoint).
• tools/verify-vm/targets.yaml — entries for the 3 new modules with honest "no Vagrant box covers this yet" notes for pintheft (needs Arch) and udisks_libblockdev (needs active console session + udisks2 installed).

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SKELETONKEY v0.7.1 — arm64-static binary + per-module arch_support

Point release on top of v0.7.0. Two additions:

1. skeletonkey-arm64-static is now published alongside the existing x86_64-static binary. Built native-arm64 in Alpine via GitHub's ubuntu-24.04-arm runner pool. Works on Raspberry Pi 4+, Apple Silicon Linux VMs, AWS Graviton, Oracle Ampere, Hetzner ARM, and any other aarch64 Linux. install.sh auto-picks it.

2. arch_support per module — a new field on struct skeletonkey_module that honestly labels which architectures the exploit() body has been verified on. Three categories:

   • any (4 modules): pwnkit, sudo_samedit, sudoedit_editor, pack2theroot. Purely userspace; arch-independent.
   • x86_64 (1 module): entrybleed. KPTI prefetchnta side-channel; x86-only by physics (ARM uses TTBR_EL0/EL1 split, not CR3). Already gated in source — returns PRECOND_FAIL on non-x86_64.
   • x86_64+unverified-arm64 (26 modules): kernel-exploitation code that hasn't been verified on arm64 yet. detect() works everywhere (it just reads ctx->host); the exploit() body uses primitives (msg_msg sprays, ROP-style finishers, specific struct offsets) that are likely portable to aarch64 but unproven.

   --list adds an ARCH column; --module-info adds an arch support: line; --scan --json adds an arch_support field per module.

What an arm64 user gets today: the full detection/triage workflow works as well as on x86_64 (--scan, --explain, --module-info, --detect-rules, --auto --dry-run). Four exploit modules (pwnkit, sudo_samedit, sudoedit_editor, pack2theroot) will fire end-to-end. The remaining 26 modules currently mark themselves as "x86_64 verified; arm64 untested" — the bug class is generic but the exploitation hasn't been confirmed. Future arm64-Vagrant verification sweeps will promote modules to any as they're confirmed.

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From v0.7.0 — empirical verification + operator briefing

The headline change since v0.6.0: 22 of 26 CVEs are now empirically confirmed against real Linux kernels in VMs, with verification records baked into the binary and surfaced in --list, --module-info, and --explain. The four still-unverified entries (vmwgfx, dirty_cow, dirtydecrypt, fragnesia) are blocked by their target environment (VMware-only, ≤4.4 kernel, Linux 7.0 not yet shipping), not by missing code — see tools/verify-vm/targets.yaml for the rationale.

Install

Pre-built binaries below (x86_64 dynamic, x86_64 static-musl, arm64 dynamic; all checksum-verified). Recommended for new installs:

curl -sSL https://github.com/KaraZajac/SKELETONKEY/releases/latest/download/install.sh | sh
skeletonkey --version

Static-musl x86_64 is the default — works back to glibc 2.17, no library dependencies.

What's in this release

Empirical verification (the big one)

• tools/verify-vm/ — Vagrant + Parallels scaffold. Boots known-vulnerable kernels (stock distro or mainline via kernel.ubuntu.com/mainline/), runs --explain --active per module, records match/mismatch as JSONL.
• 22 modules confirmed end-to-end across Ubuntu 18.04 / 20.04 / 22.04 + Debian 11 / 12 + mainline kernels 5.15.5 / 6.1.10.
• Per-module verified_on[] table baked into the binary. --list adds a VFY column showing ✓ per verified module; footer prints 31 modules registered · 10 in CISA KEV (★) · 22 empirically verified in real VMs (✓).
• --module-info <name> adds a --- verified on --- section.
• --explain <name> adds a VERIFIED ON section.

--explain MODULE — one-page operator briefing

A single command renders, for any module: CVE / CWE / MITRE ATT&CK / CISA KEV status, host fingerprint, live detect() trace with verdict and interpretation, OPSEC footprint (what an exploit would leave on this host), detection-rule coverage matrix, and verification records. Paste-ready for triage tickets and SOC handoffs.

CVE metadata pipeline

tools/refresh-cve-metadata.py fetches CISA's Known Exploited Vulnerabilities catalog + NVD CWE classifications, generates docs/CVE_METADATA.json + docs/KEV_CROSSREF.md + the in-binary lookup table. 10 of 26 modules cover KEV-listed CVEs. MITRE ATT&CK technique mapping (T1068 by default; T1611 for container escapes; T1082 for kernel info leaks). All surfaced in --list (★ column), --module-info, --explain, and --scan --json (new triage sub-object per module).

Per-module OPSEC notes

Every module's struct now carries an opsec_notes paragraph describing the runtime telemetry footprint: file artifacts, dmesg signatures, syscall observables, network activity, persistence side effects, cleanup behavior. Grounded in source + existing detection rules — the inverse of what the auditd/sigma/yara/falco rules look for. Surfaced in --module-info (text + JSON) and --explain.

119 detection rules across all 4 SIEM formats

Previously: auditd everywhere, sigma on top-10, yara/falco only on a handful. Now: 30/31 auditd, 31/31 sigma, 28/31 yara, 30/31 falco (the 3 remaining gaps are intentional skips — entrybleed is a pure timing side-channel with no syscall/file footprint; ptrace_traceme and sudo_samedit are pure-memory races with no on-disk artifacts).

Test harness

88 tests on every push: 33 kernel_range / host-fingerprint unit tests (tests/test_kernel_range.c — boundary conditions, NULL safety, multi-LTS, mainline-only) + 55 detect() integration tests (tests/test_detect.c — synthetic host fingerprints across 26 modules). Coverage report at the end identifies any modules without direct test rows.

core/host.c shared host-fingerprint refactor

One probe of kernel / arch / distro / userns gates / apparmor / selinux / lockdown / sudo + polkit versions at startup. Every module's detect() consumes ctx->host. Adds meltdown_mitigation[] passthrough so entrybleed can distinguish "Not affected" (CPU immune; OK) from "Mitigation: PTI" (KPTI on; vulnerable to EntryBleed) without re-reading sysfs.

kernel_range drift detector

tools/refresh-kernel-ranges.py polls Debian's security tracker and reports drift between the embedded kernel_patched_from tables and what Debian actually ships. Already used to apply 9 corpus fixes in v0.7.0; 9 more TOO_TIGHT findings pending per-commit verification.

Marketing-grade landing page

karazajac.github.io/SKELETONKEY — animated hero, --explain showcase with line-by-line typed terminal, bento-grid features, KEV / verification stat chips. New Open Graph card renders correctly on Twitter/LinkedIn/Slack/Discord.

Real findings from the verifier

A handful of cases that show the project's "verified-vs-claimed bar" thesis paying off in real time:

• dirty_pipe on Ubuntu 22.04 (5.15.0-91-generic) — version-only check would say VULNERABLE (5.15.0 < 5.15.25 backport in our table), but Ubuntu has silently backported the fix into the -91 patch level. --active correctly identified the primitive as blocked → OK. Only an empirical probe can tell.
• af_packet on Ubuntu 18.04 (4.15.0-213-generic) — our target expectation was wrong; 4.15 is post-fix. Caught + corrected by the verifier sweep.
• sudoedit_editor on Ubuntu 22.04 — sudo 1.9.9 is the vulnerable version, but the default vagrant user has no sudoers grant to abuse. detect() correctly returns PRECOND_FAIL ("vuln version present, no grant to abuse").

Coverage by audience

• Red team: --auto ranks vulnerable modules by safety + runs the safest, OPSEC notes per exploit, JSON for pipelines, no telemetry.
• Blue team: 119 detection rules in all 4 SIEM formats, CISA KEV prioritization, MITRE ATT&CK + CWE annotated, --explain triage briefings.
• Researchers: Source is the docs. CVE metadata sourced from federal databases. --explain shows the reasoning chain. 22 VM confirmations for trust.
• Sysadmins: --scan works without sudo. Static-musl binary drops on any Linux. JSON output for CI gates.

Compatibility

• Default install: static-musl x86_64 — works on every Linux back to glibc 2.17 (RHEL 7, Debian 9, Ubuntu 14.04+, Alpine, anything).
• Also published: dynamic x86_64 (faster, modern glibc only) and dynamic arm64 (Raspberry Pi 4+, Apple Silicon Linux VMs, ARM servers).

Authorized testing only

SKELETONKEY runs real exploits. By using it you assert you have explicit authorization to test the target system. See docs/ETHICS.md.

Links

• CVE inventory
• Verification records
• KEV cross-reference
• Detection playbook
• Architecture
• Roadmap