The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

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.

Issue 1: (Remote Source Disclosure) - Description - nginx 0.8.36 is a multi platform HTTP server. This vulnerability exists in the latest Windows version of the application available. nginx on Windows is vulnerable to a remote source disclosure attack. - Technical Details - (Source Download) http://[ webserver IP][:port]index.html::$DATA Issue 2: (Remote DoS (w/ Memory Corruption)) - Description - nginx 0.8.36 (Windows) does not seem to handle encoded directory traversal attempts properly. The corrupted registers in the crash dump seem to be loaded with damaged path variables. - Technical Details - (Remote DoS) http://[ webserver IP][:port]/%c0.%c0./%c0.%c0./%c0.%c0./%c0.%c0./%20 http://[ webserver IP][:port]/%c0.%c0./%c0.%c0./%c0.%c0./%20 http://[ webserver IP][:port]/%c0.%c0./%c0.%c0./%20 These three attempts will overwrite memory registers with different parts of the internal path based on where they try and traverse to.