viernes, 11 de junio de 2010

:::SPAS3C-SV-001:::NGINX [ENGINE X] SERVER <= 0.7.65 /0.8.39 SOURCE CODE DISCLOSURE/DOWNLOAD VULN. (CVE-2010-2263)

I found this vulnerability one week ago, but I was waiting a fucking CVE number when somebody published a similar advisory without checking. This researcher made a public disclosure in an old release and he also said that it isn't fixed when this is fake (at least Source Code Disclosure/Download got fixed with lastest releases).

Copied from ChangeLog for 0.8.40/0.7.66 (Final releases in stable/development channel):

-------------------------START-COPY-------------------------------

Changes with nginx 0.8.40 07 Jun 2010

*) Security: now nginx/Windows ignores default file stream name.
Thanks to Jose Antonio Vazquez Gonzalez.

*) Feature: the ngx_http_uwsgi_module.
Thanks to Roberto De Ioris.

*) Feature: a "fastcgi_param" directive with value starting with
"HTTP_" overrides a client request header line.

*) Bugfix: the "If-Modified-Since", "If-Range", etc. client request
header lines were passed to FastCGI-server while caching.

*) Bugfix: listen unix domain socket could not be changed during
reconfiguration.
Thanks to Maxim Dounin.

-------------------------END-COPY-------------------------------

But vulnerabilities databases seem that they didn't confirm nothing.

This is my advisory:

-------------------------START-ADVISORY-------------------------------

TITLE: NGINX [ENGINE X]
SERVER <= 0.7.65 (STABLE)/0.8.39 (DEVELOPMENT) SOURCE CODE DISCLOSURE/DOWNLOAD VULNERABILITY TESTED OS: WINDOWS XP SP3/ WINDOWS 7 HOME PREMIUM SEVERITY: HIGH CVE-NUMBER: CVE-2010-2263 IMPACT: READ/DOWNLOAD SOURCE CODE OF WEB APP FILES DISCOVERED DATE: 2010-06-04 FIXED DATE: 2010-06-07 FIXED VERSIONS: NGINX/0.8.40 AND NGINX/0.7.66 DISCOVERED BY: JOSE ANTONIO VAZQUEZ GONZALEZ ======ABOUT APPLICATION======
"nginx [engine x] is a HTTP and reverse proxy server, as well as a mail proxy server written by Igor Sysoev. It has been running for more than five years on many heavily loaded Russian sites including Rambler (RamblerMedia.com). According to Netcraft nginx served or proxied 4.70% busiest sites in April 2010. Here are some of success stories: FastMail.FM, Wordpress.com. The sources are licensed under 2-clause BSD-like license." copied from -> http://nginx.org/en/ [ref-1]

======TESTED VERSIONS=====

Unix versions are not vulnerable (it only affects to NTFS file system)

Windows Stable versions:

nginx/0.7.66 --> Not vulnerable
nginx/0.7.65 --> Vulnerable
nginx/0.7.64 --> Vulnerable
nginx/0.7.63 --> Vulnerable
nginx/0.7.62 --> Vulnerable
nginx/0.7.61 --> Vulnerable
nginx/0.7.60 --> Vulnerable
nginx/0.7.59 --> Vulnerable
nginx/0.7.58 --> Vulnerable
nginx/0.7.56 --> Vulnerable

Windows Development versions:

nginx/0.8.40 --> Not vulnerable
nginx/0.8.39 --> Vulnerable
nginx/0.8.38 --> Vulnerable
nginx/0.8.37 --> Vulnerable
nginx/0.8.36 --> Vulnerable
nginx/0.8.35 --> Vulnerable
nginx/0.8.34 --> Vulnerable
nginx/0.8.33 --> Vulnerable
nginx/0.8.32 --> Vulnerable
nginx/0.8.31 --> Vulnerable
nginx/0.8.30 --> Vulnerable

======DESCRIPTION======

This application was vulnerable to source code disclosure/download vulnerability when it was running in Windows OS (NTFS file system).
App parser couldn't handle ADS (Alternate Data Streams) and it treated a data stream as an usual file. An Attacker could read/download source code of webapps files using default data stream (unnamed): "filename::$data".

This issue is like an old security issue in Microsoft Windows IIS [ref-2].

======PROOF OF CONCEPT======

http://[IP]/[FILE]::$data

======STEPS TO REPRODUCE======

1.- Start the server.

2.- Go to http://127.0.0.1/index.html::$data

3.- Browser requests to download...yes...go to file and open it.

======REFERENCES======

[ref-1] -> http://nginx.org/
[ref-2] -> http://www.microsoft.com/technet/security/bulletin/ms98-003.mspx


======DISCLOSURE TIMELINE======

Standard Time Zone: GMT/UTC + 01:00 hour (Spain/Madrid)

[2010-06-04] => Inicial contact with vendor and sent advisory.
[2010-06-04] => Vendor response and believe that vulnerability got fixed with previous release.
[2010-06-04] => I confirm that nginx is vulnerable in Windows 7 OS.
[2010-06-04] => Vendor will try to see the issue.
[2010-06-04] => Vendor confirms the issue and he will get fixed on Monday.
[2010-06-07] => New releases out.
[2010-06-07] => I sent complete advisory and propose as disclosure date on Wednesday.
[2010-06-10] => Second chance to confirm public disclosure.
[2010-06-10] => Vendor agree.
[2010-06-11] => Forced to public disclosure.

======CREDITS=======

Jose Antonio Vazquez Gonzalez,
Telecom. Engineer & Sec. Researcher.
http://spa-s3c.blogspot.com/

Thanks to Ruben Santamarta (@reversemode) and Jose Maria Alonso (@maligno) for their support in other issues.

-------------------------END-ADVISORY-------------------------------

This is a visual Proof Of Concept:

video

Watch on youtube -> http://www.youtube.com/watch?v=DvQtvV8kQhY

Be good (responsible disclosure) has disadvantages...bye bye my first software advisory :(

Update: Thanks to exploits-db and security-focus because they (will) have updated their databases and (will) have published my advisory.

Be safe ;)

2 comentarios:

Chap0 dijo...

Great work on responsible disclosure, and a very good find for an exploit. Keep up the work on finding the bugs :D

José A. Vázquez dijo...

Thanks Chap0. I've also seen your work (and from your team) and it's awesome!

kind regards.