OSI Security - Penetration Testing & Web Application Security Consultants
  • Home
  • Try
  • Pricing
  • Services
    • Managed Monthly Penetration Testing Service
    • Managed Quarterly Penetration Testing Service
    • Email Security Review
    • Request a quote for Penetration Testing
    • Bug Bounty Penetration Test
    • Remote Support
  • Solutions
  • Company
    • Advisories
    • Customers
    • News and Press Releases
    • Blog
    • Contact
    • Careers
  • Home
  • Try
  • Pricing
  • Services
    • Managed Monthly Penetration Testing Service
    • Managed Quarterly Penetration Testing Service
    • Email Security Review
    • Request a quote for Penetration Testing
    • Bug Bounty Penetration Test
    • Remote Support
  • Solutions
  • Company
    • Advisories
    • Customers
    • News and Press Releases
    • Blog
    • Contact
    • Careers

Apache OptionsBleed Information Leak

18/9/2017

 
There have been reports of a new remote information disclosure vulnerability in Apache HTTP Server, when the HTTP "OPTIONS" method is enabled and a misconfiguration occurs. While the misconfiguration trigger seems rare in production environments, the Apache .htaccess file ability enables users of virtual hosting services to intentionally introduce the bug in a shared environment and thus be able to abuse the vulnerability condition.

​The bug has been assigned CVE-2017-9798 and reportedly affects the latest Apache release. There is a proof of concept example available to trigger the fault, however after hours of testing at OSI Security we were unable to reproduce the information leak.

Reportedly, it only occurs in high traffic Apache websites and the examples used were from the Alexa Top 400 Global Websites, where the author noticed HTTP responses that included abnormal returned bytes of system memory outside of expected use, or HTTP server content destined for other website visitors / cached in memory.

Example request:


OPTIONS /index.html HTTP/1.0

Example vulnerable response:

HTTP/1.0 200 OK
Allow: GET,HEAD,OPTIONS,,HEAD,,HEAD,,HEAD,, HEAD,,HEAD,,HEAD,,HEAD,POST,,HEAD,, HEAD,!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"

It is clear from the disclosed example, that the Allow header should only include GET, HEAD and OPTIONS (or others such as PUT and DELETE) however the server leaks information from other memory locations.

The vulnerability is reportedly triggered where the Apache server is used, with the OPTIONS request enabled, with a <Directory> definition (or a .htaccess file) which contains a e.g. <Limit GET> access control which contains an invalid method name. An example would be <Limit GETT>, as a system administrator introduced typo.

At this stage the vulnerability appears to be impractical and of low risk, however we suggest checking your Apache server configuration for Limit directives which may contain errors.

At the same time as this report, during a client penetration test we discovered a minimal risk/impact vulnerability in the latest release of Apache which we reported to the security team. The bug has since been patched in source code and should be included in the next stable release. 
    View my profile on LinkedIn

    Archives

    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    December 2015
    August 2015
    April 2014
    May 2013
    April 2013
    July 2012
    May 2012
    November 2011
    August 2011
    July 2011
    February 2011
    January 2011
    October 2010
    August 2010
    June 2010

    Categories

    All
    Apache
    Backdoor
    Best Practice
    Configuration
    Credentials
    Desktop
    DNS
    Encryption
    Exploit
    Firewall
    Hardening
    HTTP
    HTTP/S
    IDS
    Information Disclosure
    Linux
    Malware
    Man-in-the-middle
    Newsletter
    Patch
    Policy
    Samba
    Server
    Service
    SMB
    SMTP
    Unix
    VPN
    Vulnerability
    Web Browser
    Web Server
    Zero Day

    RSS Feed

NSW Government ICT Services (SCM0020) approved supplier
OSI Security is an approved supplier to the Victorian Government
OSI Security is an approved supplier to the Queensland Government
OSI Security is an approved supplier to the New Zealand Government
Picture
External Penetration Testing
Managed Security Services
​Source Code Review
Web Application Security Testing
Firewall Configuration and Rulesets
WiFi Access Point and Client Auditing
Forensics and Data Recovery
System Hardening and Configuration
Metasploit Pro
Tenable Nessus
Acunetix Web Scanner
Nexpose Vulnerability
Secunia Software Inspection
Elcomsoft Password Cracking
PortSwigger BurpSuite
HP Fortify
 
Contact
Clients
Advisories
Privacy policy
​
Ethics Statement
Disclosure Policy
OSI SECURITY ACN 144 579 751 © 2010 - 2025.
​ALL RIGHTS RESERVED. SYDNEY, AUSTRALIA.
Join newsletter

Picture

OSI Security is proud to support a number of recognised charities, development projects and industry groups...

The Australian Computer Museum Society Incorporated
Hackers Helping Hackers
sqlmap.org
Metasploit Framework
2600-AU Australia