Vulnerability in Microsoft HTTP.sys Could Allow Remote Code Execution (MS15-034)

ITS Advisory Number: 
2015-041 - UPDATED
Date(s) Issued: 
Tuesday, April 14, 2015
Date Updated: 
Thursday, April 16, 2015
Subject: 
Vulnerability in Microsoft HTTP.sys Could Allow Remote Code Execution (MS15-034)
Overview: 

A vulnerability has been discovered in the HTTP protocol stack (HTTP.sys) that could allow remote code execution. An attacker who successfully exploited this vulnerability could execute arbitrary code in the context of the System account. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

APRIL 16 UPDATED OVERVIEW

Exploit code for this vulnerability is now publicly available and is being exploited in the wild. 

 

Systems Affected: 
  • Windows 7
  • Windows Server 2008 R2
  • Windows 8
  • Windows 8.1
  • Windows Server 2012
  • Windows Server 2012 R2
RISK
GOVERNMENT
Large and medium government entities: 
High
Small government entities: 
High
BUSINESS
Large and medium business entities: 
High
Small business entities: 
High
Home Users: 
High
Description: 

A vulnerability has been discovered in the HTTP protocol stack (HTTP.sys) that could allow remote code execution. HTTP.sys provides the following services in IIS:

  • Routing HTTP requests to the correct request queue.
  • Caching of responses in kernel mode.
  • Performing all text-based logging for the WWW service.
  • Implementing Quality of Service (QoS) functionality, which includes connection limits, connection timeouts, queue-length limits, and bandwidth throttling.

This vulnerability can be triggered by sending a specially crafted HTTP request to an affected system.

Successful exploitation of this vulnerability could result in an attacker executing arbitrary code in the context of the System account when parsed by HTTP.sys. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

Actions: 

We recommend the following actions be taken:

  • Apply appropriate patches provided by Microsoft to vulnerable systems immediately after appropriate testing.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • Do not open email attachments from unknown or untrusted sources or suspicious emails from trusted sources.
  • Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources.