Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Vulnerabilities / Threats

6/21/2017
07:15 PM
Connect Directly
Twitter
RSS
E-Mail
50%
50%

'Stack Clash' Smashed Security Fix in Linux

Linux, OpenBSD, Free BSD, Solaris security updates available to thwart newly discovered attack by researchers.

What's old is new again: an exploit protection mechanism for a known flaw in the Linux kernel has fallen to a new attack targeting an old problem.

The so-called Stack Clash vulnerability, which was discovered and disclosed by Qualys, affects Linux, OpenBSD, NetBSD, FreeBSD, and Solaris, on i386 and amd64 processors. These platforms earlier this week received patches for the vulnerability, a memory management flaw in the Linux kernel that could allow attackers to bypass security controls previously put in place to prevent memory management attacks on Linux-based servers, appliances, and even Internet of Things devices.

Qualys developed seven exploits and proof-of-concepts to demonstrate the vulnerability, which could be used by an attacker to corrupt memory and run malicious code and ultimately gain control of a targeted machine. Researchers at Qualys are urging organizations to update their Linux plaforms immediately for the flaw.

"It [the flaw] has to do with the memory management of these systems, so it's widespread in terms of scope," says Jimmy Graham, director of the product protection team at Qualys. Graham says it allows a privilege escalation-type attack.

What makes this particular vulnerability unique is that it bypasses controls and mitigations that Linux developers put in place to prevent memory-management attacks. "It shows that the specific mitigation is not effective," he says.

The attack that StackClash executes really isn't new: The concept of the memory management/pressure attack was first employed by researchers in 2005, and again in 2010. Linux developers responded to those disclosures with the so-called StackGuard Page security mitigation for the operating system - which Stack Clash cheats. "We bypassed StackGuard Page … to jump into [Linux] memory," Graham notes.

Stack Clash, which require local access to the targeted Linux machine, works like this: it overwrites a region in the kernel memory called the stack, causing confusion in the memory and allowing an attacker to "clash" with another memory region. Qualys researchers used local privilege escalation exploits against the flaw to gain full root privileges to the targeted system.

What makes the attack especially dangerous is that it can be "chained" with another vulnerability to escalate into a deeper and more pervasive attack. An attacker could employ SQL injection as well and escalate the attack to reach other shared systems in the victim organization, according to Qualys, specifically in shared, multi-tenant systems.

"This affects any kind of Linux or BSD system – appliances to back-end equipment to Web servers," Graham says.

Don Bailey, founder and CEO of Lab Mouse Security, says while these memory pressure vulnerabilities have been well-documented, Stack Clash demonstrates just how widely these flaws can be exploited by attackers.

"The design of the operating system and how it reacts to memory pressure: that's fascinating research. This opens a whole new world of embedded systems that rely on Linux … which can be vulnerable as well to this style of attacks," he says. And the obvious problem of little or no patching of embedded systems puts them even more at risk.

While Stack Clash is a local attack, Qualys researchers haven't ruled out the possibility of remote attacks via the flaw as well.

"Our research has mainly focused on local exploitation: as of this writing on June 19, 2017, we do not know of any remotely exploitable application. However, remote exploitation of the Stack Clash is not excluded; although local exploitation will always be easier, and remote exploitation will be very application-specific," Qualys wrote in a blog post on the attack.

Qualys also published technical details on Stack Clash (CVE-2017-1000364), in a security advisory as well as related flaws CVE-2017-1000365), and CVE-2017-1000367).

Related Content:

Black Hat USA returns to the fabulous Mandalay Bay in Las Vegas, Nevada, July 22-27, 2017. Click for information on the conference schedule and to register.

Kelly Jackson Higgins is the Executive Editor of Dark Reading. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise ... View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Attackers Leave Stolen Credentials Searchable on Google
Kelly Sheridan, Staff Editor, Dark Reading,  1/21/2021
How to Better Secure Your Microsoft 365 Environment
Kelly Sheridan, Staff Editor, Dark Reading,  1/25/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win an Amazon Gift Card! Click Here
Latest Comment: We need more votes, check the obituaries.
Current Issue
2020: The Year in Security
Download this Tech Digest for a look at the biggest security stories that - so far - have shaped a very strange and stressful year.
Flash Poll
Assessing Cybersecurity Risk in Today's Enterprises
Assessing Cybersecurity Risk in Today's Enterprises
COVID-19 has created a new IT paradigm in the enterprise -- and a new level of cybersecurity risk. This report offers a look at how enterprises are assessing and managing cyber-risk under the new normal.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2021-3317
PUBLISHED: 2021-01-26
KLog Server through 2.4.1 allows authenticated command injection. async.php calls shell_exec() on the original value of the source parameter.
CVE-2013-2512
PUBLISHED: 2021-01-26
The ftpd gem 0.2.1 for Ruby allows remote attackers to execute arbitrary OS commands via shell metacharacters in a LIST or NLST command argument within FTP protocol traffic.
CVE-2021-3165
PUBLISHED: 2021-01-26
SmartAgent 3.1.0 allows a ViewOnly attacker to create a SuperUser account via the /#/CampaignManager/users URI.
CVE-2021-1070
PUBLISHED: 2021-01-26
NVIDIA Jetson AGX Xavier Series, Jetson Xavier NX, TX1, TX2, Nano and Nano 2GB, L4T versions prior to 32.5, contains a vulnerability in the apply_binaries.sh script used to install NVIDIA components into the root file system image, in which improper access control is applied, which may lead to an un...
CVE-2021-1071
PUBLISHED: 2021-01-26
NVIDIA Tegra kernel in Jetson AGX Xavier Series, Jetson Xavier NX, TX1, TX2, Nano and Nano 2GB, all L4T versions prior to r32.5, contains a vulnerability in the INA3221 driver in which improper access control may lead to unauthorized users gaining access to system power usage data, which may lead to...