39ce4dff09089bf7869f1d72a7f4f759cca75dc4
5 Commits
| Author | SHA1 | Message | Date | |
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 leviathan
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39ce4dff09 |
modules: per-module OPSEC notes — telemetry footprint per exploit
Adds .opsec_notes to every module's struct skeletonkey_module
(31 entries across 26 module files). One paragraph per exploit
describing the runtime footprint a defender/SOC would see:
- file artifacts created/modified (exact paths from source)
- syscall observables (the unshare / socket / setsockopt /
splice / msgsnd patterns the embedded detection rules look for)
- dmesg signatures (silent on success vs KASAN oops on miss)
- network activity (loopback-only vs none)
- persistence side-effects (/etc/passwd modification, dropped
setuid binaries, backdoors)
- cleanup behaviour (callback present? what it restores?)
Each note is grounded in the module's source code + its existing
auditd/sigma/yara/falco detection rules — the OPSEC notes are
literally the inverse of those rules (the rules describe what to
look for; the notes describe what the exploit triggers).
Three intelligence agents researched the modules in parallel,
reading source + MODULE.md, then their proposals were embedded
verbatim via tools/inject_opsec.py (one-shot script, not retained).
Where surfaced:
- --module-info <name>: '--- opsec notes ---' section between
detect-rules summary and the embedded auditd/sigma rule bodies.
- --module-info / --scan --json: 'opsec_notes' top-level string.
Audience uses:
- Red team: see what footprint each exploit leaves so they pick
chains that match the host's telemetry posture.
- Blue team: the notes mirror the existing detection rules from the
attacker side — easy diff to find gaps in their SIEM coverage.
- Researchers: per-exploit footprint catalog for technique analysis.
copy_fail_family gets one shared note across all 5 register entries
(copy_fail, copy_fail_gcm, dirty_frag_esp, dirty_frag_esp6,
dirty_frag_rxrpc) since they share exploit infrastructure.
Verification:
- macOS local: clean build, --module-info nf_tables shows full
opsec section + CWE + ATT&CK + KEV row from previous commit.
- Linux (docker gcc:latest): 33 + 54 = 87 passes, 0 fails.
Next: --explain mode (uses these notes + the triage metadata to
render a single 'why is this verdict, what would patch fix it, and
what would the SOC see' page per module).
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leviathan
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8938a74d04 |
detection rules: YARA + Falco for the 6 highest-rank modules + playbook
Closes the 'rules in the box' gap — the README has claimed YARA + Falco coverage but detect_yara and detect_falco were NULL on every module. This commit lights up both formats for the 6 highest-value modules (covering 10 of 31 registered modules via family-shared rules), and the existing operational playbook gains the format-specific deployment recipes + the cross-format correlation table. YARA rules (8 rules, 9 module-headers, 152 lines): - copy_fail_family — etc_passwd_uid_flip + etc_passwd_root_no_password (shared across copy_fail / copy_fail_gcm / dirty_frag_esp / dirty_frag_esp6 / dirty_frag_rxrpc) - dirty_pipe — passwd UID flip pattern, dirty-pipe-specific tag - dirtydecrypt — 28-byte ELF prefix match on tiny_elf[] + setuid+execve shellcode tail, detects the page-cache overlay landing - fragnesia — 28-byte ELF prefix on shell_elf[] + setuid+setgid+seteuid cascade, detects the 192-byte page-cache overlay - pwnkit — gconv-modules cache file format (small text file with module UTF-8// X// /tmp/...) - pack2theroot — malicious .deb (ar archive + SUID-bash postinst) + /tmp/.suid_bash artifact scan Falco rules (13 rules, 9 module-headers, 219 lines): - pwnkit — pkexec with empty argv + GCONV_PATH/CHARSET env from non-root - copy_fail_family — AF_ALG socket from non-root + NETLINK_XFRM from unprivileged userns + /etc/passwd modified by non-root - dirty_pipe — splice() of setuid/credential file by non-root - dirtydecrypt — AF_RXRPC socket + add_key(rxrpc) by non-root - fragnesia — TCP_ULP=espintcp from non-root + splice of setuid binary - pack2theroot — SUID bit set on /tmp/.suid_bash + dpkg invoked by packagekitd with /tmp/.pk-*.deb + 2x InstallFiles on same transaction Wiring: each module's .detect_yara and .detect_falco struct fields now point at the embedded string. The dispatcher dedups by pointer, so family-shared rules emit once across the 5 sub-modules. docs/DETECTION_PLAYBOOK.md augmented (302 -> 456 lines): - New 'YARA artifact scanning' subsection under SIEM integration with scheduled-scan cron pattern + per-rule trigger table - New 'Falco runtime detection' subsection with deploy + per-rule trigger table - New 'Per-module detection coverage' table — 4-format matrix - New 'Correlation across formats' section — multi-format incident signature per exploit (the 3-of-4 signal pattern) - New 'Worked example: catching DirtyDecrypt end-to-end' walkthrough from Falco page through yara confirmation, recovery, hunt + patch The existing operational lifecycle / SIEM patterns / FP tuning content is preserved unchanged — this commit only adds. Final stats: - auditd: 109 rule statements across 27 modules - sigma: 16 sigma rules across 19 modules - yara: 8 yara rules across 9 module headers (5 family + 4 distinct) - falco: 13 falco rules across 9 module headers The remaining 21 modules can gain YARA / Falco coverage incrementally by populating their detect_yara / detect_falco struct fields. |
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leviathan
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ea1744e6f0 |
tests: detect() unit harness with mocked ctx->host
Adds tests/test_detect.c — a standalone harness that constructs synthetic struct skeletonkey_host fingerprints (vulnerable / patched / specific-gate-closed) and asserts each migrated module's detect() returns the expected verdict. First real test coverage for the corpus; catches regressions in the host-fingerprint-consuming logic. Initial coverage — 8 deterministic cases across the 4 modules that already consume ctx->host: - dirtydecrypt: 3 cases verifying 'kernel < 7.0 -> predates the bug' short-circuit on synthetic 6.12 / 6.14 / 6.8 hosts. - fragnesia: unprivileged_userns_allowed=false -> PRECOND_FAIL. - pack2theroot: is_debian_family=false -> PRECOND_FAIL. - pack2theroot: has_dbus_system=false -> PRECOND_FAIL. - overlayfs: distro=debian / distro=fedora -> 'not Ubuntu' -> OK. Coverage grows automatically as more modules migrate to ctx->host (task #12 below adds them). Each new module that consults the host fingerprint can have its precondition gates tested with a one-line EXPECT_DETECT call against a pre-built fingerprint. Wiring: - Makefile: new MODULE_OBJS var consolidates the module .o list so both the main binary and the test binary can share it without duplication. New TEST_BIN := skeletonkey-test target. 'make test' builds and runs the suite. - .github/workflows/build.yml: install libglib2.0-dev + pkg-config so pack2theroot builds with GLib in CI (was previously stub-compiling). New 'tests — detect() unit suite' step runs 'make test' as a non-root user so modules' 'already root' gates don't short-circuit before the synthetic host checks fire. - Test harness compiles cross-platform but assertions are #ifdef __linux__ guarded (on non-Linux all module detect() bodies stub-out to PRECOND_FAIL, making assertions tautological); macOS dev build reports 'skipped'. Module change: - pack2theroot p2tr_detect now consults ctx->host->is_root (with a geteuid() fallback when ctx->host is null) instead of calling geteuid() directly. Production behaviour is identical (host->is_root is populated from geteuid() at startup); tests can now construct non-root fingerprints regardless of the test process's actual euid. Exposed a real consistency issue worth fixing. Verified in docker as non-root: 8/8 pass on Linux. macOS reports 'skipped' as designed. |
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leviathan
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4f30d00a1c |
core/host: shared host fingerprint refactor
Adds core/host.{h,c} — a single struct skeletonkey_host populated once
at startup and handed to every module callback via ctx->host. Replaces
the per-detect uname / /etc/os-release / sysctl / userns-fork-probe
calls scattered across the corpus with O(1) cached lookups, and gives
the dispatcher one consistent view of the host.
What's in the fingerprint:
- Identity: kernel_version (parsed from uname.release), arch (machine),
nodename, distro_id / distro_version_id / distro_pretty (parsed once
from /etc/os-release).
- Process state: euid, real_uid (defeats userns illusion via
/proc/self/uid_map), egid, username, is_root, is_ssh_session.
- Platform family: is_linux, is_debian_family, is_rpm_family,
is_arch_family, is_suse_family (file-existence checks once).
- Capability gates (Linux): unprivileged_userns_allowed (live
fork+unshare probe), apparmor_restrict_userns,
unprivileged_bpf_disabled, kpti_enabled, kernel_lockdown_active,
selinux_enforcing, yama_ptrace_restricted.
- System services: has_systemd, has_dbus_system.
Wiring:
- core/module.h forward-declares struct skeletonkey_host and adds the
pointer to skeletonkey_ctx. Modules opt-in by including
../../core/host.h.
- core/host.c is fully POD (no heap pointers) — uses a single file-
static instance, returns a stable pointer on every call. Lazily
populated on first skeletonkey_host_get().
- skeletonkey.c calls skeletonkey_host_get() at main() entry, stores
in ctx.host before any register_*() runs.
- cmd_auto's bespoke distro-fingerprint code (was an inline
read_os_release helper) is replaced with skeletonkey_host_print_banner(),
which emits a two-line banner of identity + capability gates.
Migrations:
- dirtydecrypt: kernel_version_current() -> ctx->host->kernel.
- fragnesia: removed local fg_userns_allowed() fork-probe in favour of
ctx->host->unprivileged_userns_allowed (no per-scan fork). Also
pulls kernel from ctx->host. The PRECOND_FAIL message now notes
whether AppArmor restriction is on.
- pack2theroot: access('/etc/debian_version') -> ctx->host->is_debian_family;
also short-circuits when ctx->host->has_dbus_system is false (saves
the GLib g_bus_get_sync attempt on systems without system D-Bus).
- overlayfs: replaced the inline is_ubuntu() /etc/os-release parser
with ctx->host->distro_id comparison. Local helper preserved for
symmetry / standalone builds.
Documentation: docs/ARCHITECTURE.md gains a 'Host fingerprint'
section describing the struct, the opt-in include pattern, and
example detect() usage. ROADMAP --auto accuracy log notes the
landing and flags remaining modules as an incremental follow-up.
Build verification:
- macOS (local): make clean && make -> Mach-O x86_64, 31 modules,
banner prints with distro=?/? (no /etc/os-release).
- Linux (docker gcc:latest + libglib2.0-dev): make clean && make ->
ELF 64-bit, 31 modules. Banner prints with kernel + distro=debian/13
+ 7 capability gates. dirtydecrypt correctly says 'predates the
rxgk code added in 7.0'; fragnesia PRECOND_FAILs with
'(host fingerprint)' annotation; pack2theroot PRECOND_FAILs on
no-DBus; overlayfs reports 'not Ubuntu (distro=debian)'.
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leviathan
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9a4cc91619 |
pack2theroot (CVE-2026-41651) + --auto accuracy work
Adds the third ported module — Pack2TheRoot, a userspace PackageKit
D-Bus TOCTOU LPE — and spends real effort hardening --auto so its
detect step gives an accurate, robust verdict before deploying.
pack2theroot (CVE-2026-41651):
- Ported from the public Vozec PoC
(github.com/Vozec/CVE-2026-41651). Original disclosure by the
Deutsche Telekom security team.
- Two back-to-back InstallFiles D-Bus calls (SIMULATE then NONE)
overwrite the cached transaction flags between polkit auth and
dispatch. GLib priority ordering makes the overwrite deterministic,
not a timing race; postinst of the malicious .deb drops a SUID bash
in /tmp.
- detect() reads PackageKit's VersionMajor/Minor/Micro directly over
D-Bus and compares against the pinned fix release 1.3.5 (commit
76cfb675). This is a high-confidence verdict, not precondition-only.
- Debian-family only (PoC builds its own .deb in pure C; ar/ustar/
gzip-stored inline). Cleanup removes /tmp .debs + best-effort
unlinks /tmp/.suid_bash + sudo -n dpkg -r the staging packages.
- Adds an optional GLib/GIO build dependency. The top-level Makefile
autodetects via `pkg-config gio-2.0`; when absent the module
compiles as a stub returning PRECOND_FAIL.
- Embedded auditd + sigma rules cover the file-side footprint
(/tmp/.suid_bash, /tmp/.pk-*.deb, non-root dpkg/apt execve).
--auto accuracy improvements:
- Auto-enables --active before the scan. Per-module sentinel probes
(page-cache /tmp files, fork-isolated namespace mounts) turn
version-only checks into definitive verdicts, so silent distro
backports don't fool the scan and --auto won't pick blind on
TEST_ERROR.
- Per-module verdict printing — every module's result is shown
(VULNERABLE / patched / precondition / indeterminate), not just
VULNERABLE rows. Operator sees the full picture.
- Scan-end summary line: "N vulnerable, M patched/n.a., K
precondition-fail, L indeterminate" with a separate callout when
modules crashed.
- Distro fingerprint added to the auto banner (ID + VERSION_ID from
/etc/os-release alongside kernel/arch).
- Fork-isolated detect() — each detector runs in a child process so
a SIGILL/SIGSEGV in one module's probe is contained and the scan
continues. Surfaced live while testing: entrybleed's prefetchnta
KASLR sweep SIGILLs on emulated CPUs (linuxkit on darwin); without
isolation the whole --auto died at module 7 of 31. With isolation
the scan reports "detect() crashed (signal 4) — continuing" and
finishes cleanly.
module_safety_rank additions:
- pack2theroot: 95 (userspace D-Bus TOCTOU; dpkg + /tmp SUID footprint
— clean but heavier than pwnkit's gconv-modules-only path).
- dirtydecrypt / fragnesia: 86 (page-cache writes; one step below the
verified copy_fail/dirty_frag family at 88 to prefer verified
modules when both apply).
Docs:
- README badge / tagline / tier table / ⚪ block / example output /
v0.5.0 status — all updated to "28 verified + 3 ported".
- CVES.md counts line, the ported-modules note (now calling out
pack2theroot's high-confidence detect vs. precondition-only for
the page-cache pair), inventory row, operations table row.
- ROADMAP Phase 7+: pack2theroot moved out of carry-overs into the
"landed (ported, pending VM verification)" group; added a new
"--auto accuracy work" subsection documenting the dispatcher
hardening landed in this commit.
- docs/index.html: scanning-count example bumped to 31, status line
updated to mention 3 ported modules.
Build verification: full `make clean && make` in `docker gcc:latest`
with libglib2.0-dev installed: links into a 31-module skeletonkey
ELF (413KB), `--list` shows all modules including pack2theroot,
`--detect-rules --format=auditd` emits the new pack2theroot section,
`--auto --i-know --no-shell` exercises the new banner + active
probes + verdict table + fork isolation + scan summary end-to-end.
Only build warning is the pre-existing
`-Wunterminated-string-initialization` in dirty_pipe (not introduced
here).
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