Vulnerabilities / Threats
10/28/2010
12:29 PM
50%
50%

Microsoft Windows Still Vulnerable To DLL Hijacking

Even patched applications aren't safe from bug, says ACROS security researcher.

Image Slideshow: Windows 7 Revealed
(click image for larger view)
Slideshow: Windows 7 Revealed

Even patched Windows applications remain vulnerable to dynamic link library (DLL) hijacking -- aka DLL planting and DLL loading -- attacks due to the erratic way in which Windows attempts to load DLLs.

That warning comes from a security advisory released on Wednesday by ACROS Security.

How can attackers take advantage of the DLL vulnerability? According to Microsoft: "When an application dynamically loads a dynamic link library (DLL) without specifying a fully qualified path name, Windows tries to locate the DLL by searching a well-defined set of directories. If an attacker gains control of one of the directories, they can force the application to load a malicious copy of the DLL instead of the DLL that it was expecting." As a result, attackers can execute arbitrary code using the current user's access level.

To help developers code applications that avoid this DLL-hijacking vulnerability, Microsoft had released SetDllDirectory. This function allows developers to eliminate the current working directory from Windows DLL searches, to frustrate attackers who might otherwise use that directory to hide malicious DLL files.

But developers can't rely on SetDllDirectory, because it behaves erratically, at least on Windows XP Professional 32 bit, Windows Vista Business 32 and 64 bit, and Windows 7 Professional 32 bit, said Mitja Kolsek, CEO of Acros Security.

The issue is that Windows often botches relative file location searches. "Until Microsoft fixes this bug, any application that sets user or system path can unwittingly make your application vulnerable to binary planting if you're loading libraries from relative paths," he said. Furthermore, even when developers write absolute paths, Windows may still treat them as relative ones, or alter other important variables after users log off and log back in.

To help, Kolsek urged developers to "use absolute, fully qualified paths to DLLs when loading them." While that won't block every type of DLL-hijacking attack, it will mitigate many of them.

Note that Microsoft's current DLL-hijacking hotfix does still work, at least against certain types of attacks. "This hotfix successfully blocks DLL loads from the current working directory if configured properly, even if relative locations are found in the PATH," said Kolsek. That said, it will not block executable files from exploiting the DLL hijacking vulnerability. To date, according to Secunia, a vulnerability information provider, 211 applications are vulnerable to DLL-hijacking attacks. So far, however, only 25 have been patched.

Comment  | 
Email This  | 
Print  | 
RSS
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Register for Dark Reading Newsletters
White Papers
Video
All Videos
Cartoon Contest
Current Issue
DNS Threats: What Every Enterprise Should Know
Domain Name System exploits could put your data at risk. Here's some advice on how to avoid them.
Back Issues | Must Reads
Flash Poll
Slideshows
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2013-7445
Published: 2015-10-15
The Direct Rendering Manager (DRM) subsystem in the Linux kernel through 4.x mishandles requests for Graphics Execution Manager (GEM) objects, which allows context-dependent attackers to cause a denial of service (memory consumption) via an application that processes graphics data, as demonstrated b...

CVE-2015-4948
Published: 2015-10-15
netstat in IBM AIX 5.3, 6.1, and 7.1 and VIOS 2.2.x, when a fibre channel adapter is used, allows local users to gain privileges via unspecified vectors.

CVE-2015-5660
Published: 2015-10-15
Cross-site request forgery (CSRF) vulnerability in eXtplorer before 2.1.8 allows remote attackers to hijack the authentication of arbitrary users for requests that execute PHP code.

CVE-2015-6003
Published: 2015-10-15
Directory traversal vulnerability in QNAP QTS before 4.1.4 build 0910 and 4.2.x before 4.2.0 RC2 build 0910, when AFP is enabled, allows remote attackers to read or write to arbitrary files by leveraging access to an OS X (1) user or (2) guest account.

CVE-2015-6333
Published: 2015-10-15
Cisco Application Policy Infrastructure Controller (APIC) 1.1j allows local users to gain privileges via vectors involving addition of an SSH key, aka Bug ID CSCuw46076.

Dark Reading Radio
Archived Dark Reading Radio

The cybersecurity profession struggles to retain women (figures range from 10 to 20 percent). It's particularly worrisome for an industry with a rapidly growing number of vacant positions.

So why does the shortage of women continue to be worse in security than in other IT sectors? How can men in infosec be better allies for women; and how can women be better allies for one another? What is the industry doing to fix the problem -- what's working, and what isn't?

Is this really a problem at all? Are the low numbers simply an indication that women do not want to be in cybersecurity, and is it possible that more women will never want to be in cybersecurity? How many women would we need to see in the industry to declare success?

Join Dark Reading senior editor Sara Peters and guests Angela Knox of Cloudmark, Barrett Sellers of Arbor Networks, Regina Wallace-Jones of Facebook, Steve Christey Coley of MITRE, and Chris Roosenraad of M3AAWG on Wednesday, July 13 at 1 p.m. Eastern Time to discuss all this and more.

FULL SCHEDULE | ARCHIVED SHOWS