News

Windows Patch Tuesday Hole Being Used in Zero-Day Attacks

Just one day after Microsoft released its monthly security patch, attackers had already reverse-engineered one of the bulletins and have been using it in active attacks.

According to security training firm SANS Institute, bulletin MS15-034, which resolved an issue in Windows and how it receives HTTP requests (but was not seen in the wild being used in active exploits), had been spotted in its honeypot monitoring to be used in targeted attacks against Web servers.

"The problem is that this will easily crash systems," said SANS Internet Storm Center CTO Johannes Ullrich. "It is not a denial of service, and not easily a data leakage issue like Heartbleed. But even crashing millions of IIS servers could cause significant impact, as many large sites use IIS."

System crashes can occur when the Range header in an HTTP request is manipulated to a variable that is too high for a server to handle, causing a Windows kernel crash. The flaw can be found in Windows 7, 8, 8.1, Windows Server 2008 R2, Windows Server 2012 and Windows Server 2012 R2, which all run Internet Information Services (IIS) for Windows.

SANS Institute has also shared information on how to easily check a IIS server to see if it is vulnerable in a security bulletin. Send the following request through IIS for Windows:

GET  / HTTP/1.1
Host: MS15034
Range: bytes=0-18446744073709551615

"If the server responds with 'Requested Header Range Not Satisfiable,' then you may be vulnerable," wrote SANS Institute.

The easiest solution is to apply the fix released on Tuesday as soon as possible. Furthermore, if more testing of April's patch is needed before applying it, Microsoft said a workaround is available if the IIS kernel caching is disabled. However, the company warns that performance issues may occur by doing this.  

 

About the Author

Chris Paoli is the site producer for Redmondmag.com and MCPmag.com.

Featured

  • Windows 10 Preview Adds Ability To Display Linux Distro Files

    Microsoft on Wednesday announced Windows 10 preview build 19603, which adds easier access to installed Linux distro files using Windows File Explorer.

  • Microsoft 365 Business To Get Azure Active Directory Premium P1 Perks

    Subscribers to Microsoft 365 Business (which is being renamed this month to "Microsoft 365 Business Premium") will be getting Azure Active Directory Premium P1 licensing at no additional cost.

  • How To Use .CSV Files with PowerShell, Part 1

    When it comes to bulk administration, few things are handier than .CSV files. In this two-part series, Brien demos his top techniques for working with .CSV files in PowerShell. First up: How to create a .CSV file.

  • SameSite Cookie Changes Rolled Back Until Summer

    The Chromium Project announced on Friday that it's delaying enforcement of SameSite cookie changes, and is temporarily rolling back those changes, because of the COVID-19 turmoil.

comments powered by Disqus

Office 365 Watch

Sign up for our newsletter.

Terms and Privacy Policy consent

I agree to this site's Privacy Policy.