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.

ABTV

// // //
10/11/2017
12:37 PM
Larry Loeb
Larry Loeb
Larry Loeb

Rowhammer Attack Pounds With Precision

A new variant of the Rowhammer attack can work around every known defense.

As DRAM has gotten smaller and larger in capacity, the memory cells that make it up have also gotten smaller. This has led to a kind of defect where attackers could bombard ("hammer") RAM memory cell rows with constant read-write operations thereby causing the memory cells to change their electrical charge and their logical state.

First discovered in 2014, there has been continued research into the attack over the ensuing years. It's known that DDR3 and DDR4 kinds of memory are vulnerable to it. It has also been shown that such attacks can be conducted with simple JavaScript, rather than complex malware code.

Not only that, this kind of exploit can escalate an attacker's privileges, root a device, or cause denial-of-service to services like security software. It can mess things up big time.

Memory manufacturers have tried to respond to this situation by instituting changes like looking at CPU performance counters for frequent accesses to DRAM cells and separating user and kernel memory cells by physical isolation. Intel even changed some of its CPU memory architecture to make Rowhammer attacks harder to implement.

But researchers Daniel Gruss, Moritz Lipp, Michael Schwarz, Daniel Genkin, Jonas Juffinger, Sioli O’Connell, Wolfgang Schoechl and Yuval Yarom have found a way to launch a new kind of Rowhammer attack that is able to ignore all of the defenses that have been done up to now. Instead of attacking multiple rows of cells, this new method only hammers one row of cells.

They also use a method called opcode flipping, which is a generic technique for exploiting bit flips in cached copies of binary files. In contrast to the previous Rowhammer attacks which are based on memory heap spraying (injecting data into specific parts of computer memory), the binary pages they attack cannot be sprayed and only exist for a single time in the entire memory.

This opcode flipping allows them avoid previous mitigation methods that were memory based by flipping bits in a predictable and targeted way inside the userspace Sudo binaries.

The attack is detailed in their paper "Another Flip in the Wall of Rowhammer Defenses" published this week.

The researchers say that the technique is still capable of carrying out denial-of-service attacks on cloud environments, as well as for privilege escalation on personal computers.


Want to learn more about the tech and business cases for deploying virtualized solutions in the cable network? Join us in Denver on October 18 for Light Reading's Virtualizing the Cable Architecture event – a free breakfast panel at SCTE/ISBE's Cable-Tec Expo featuring speakers from Comcast and Charter.

As an example, they were able to fool the Intel SGX (Software Guard Extensions) in order "...to hide the the full privilege-escalation attack entirely from the user and the operating system, making any inspection or detection of the attack infeasible," as they put it. The attacker in this case will run an unprivileged SGX enclave to evade defense classes.

The authors give no hints in their paper on how the attack might be mitigated, showing the depth and seriousness of the potential impact. There may be efforts currently underway to deal with it, but they have not reached the public as of now.

Related posts:

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Edge-DRsplash-10-edge-articles
I Smell a RAT! New Cybersecurity Threats for the Crypto Industry
David Trepp, Partner, IT Assurance with accounting and advisory firm BPM LLP,  7/9/2021
News
Attacks on Kaseya Servers Led to Ransomware in Less Than 2 Hours
Robert Lemos, Contributing Writer,  7/7/2021
Commentary
It's in the Game (but It Shouldn't Be)
Tal Memran, Cybersecurity Expert, CYE,  7/9/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Incorporating a Prevention Mindset into Threat Detection and Response
Threat detection and response systems, by definition, are reactive because they have to wait for damage to be done before finding the attack. With a prevention-mindset, security teams can proactively anticipate the attacker's next move, rather than reacting to specific threats or trying to detect the latest techniques in real-time. The report covers areas enterprises should focus on: What positive response looks like. Improving security hygiene. Combining preventive actions with red team efforts.
Flash Poll
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2022-25878
PUBLISHED: 2022-05-27
The package protobufjs before 6.11.3 are vulnerable to Prototype Pollution which can allow an attacker to add/modify properties of the Object.prototype. This vulnerability can occur in multiple ways: 1. by providing untrusted user input to util.setProperty or to ReflectionObject.setParsedOption ...
CVE-2021-27780
PUBLISHED: 2022-05-27
The software may be vulnerable to both Un-Auth XML interaction and unauthenticated device enrollment.
CVE-2021-27781
PUBLISHED: 2022-05-27
The Master operator may be able to embed script tag in HTML with alert pop-up display cookie.
CVE-2022-1897
PUBLISHED: 2022-05-27
Out-of-bounds Write in GitHub repository vim/vim prior to 8.2.
CVE-2022-20666
PUBLISHED: 2022-05-27
Multiple vulnerabilities in the web-based management interface of Cisco Common Services Platform Collector (CSPC) Software could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface. These vulnerabilities are due to insufficient va...