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
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 A. VAZQUEZ

======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 is 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 María Alonso (@maligno) for their support in other issues.