Connect with us

Hi, what are you looking for?

SecurityWeekSecurityWeek

Endpoint Security

Half-Double: Google Researchers Find New Rowhammer Attack Technique

A team of researchers from Google has identified a new Rowhammer attack technique that works against recent generations of dynamic random-access memory (DRAM) chips.

A team of researchers from Google has identified a new Rowhammer attack technique that works against recent generations of dynamic random-access memory (DRAM) chips.

Rowhammer attacks — first discussed in 2014 — involve repeatedly accessing a row of memory in an effort to cause bit flips in adjacent rows, which can be useful for bypassing memory protections. A malicious actor could use Rowhammer to escalate privileges and for other purposes, and researchers have demonstrated over the past years that attacks can be launched remotely and against mobile devices.

JEDEC, an organization that develops open standards and publications for the microelectronics industry, has warned that Rowhammer attacks can pose a “serious threat to cloud service providers, data centers, laptops, smart phones, self-driving cars and IoT devices.”

The vulnerability exists because the memory cells in DRAM chips have been placed very close together to increase capacity and decrease size. This makes it more difficult to prevent cells from electrically interacting with each other.

Rowhammer defenses in many cases assume that the attacker can only cause bit flips in the immediate neighbors of the row they are targeting. However, the new attack method disclosed this week by Google, which researchers have dubbed “Half-Double,” shows that the effects of Rowhammer can extend beyond immediate neighbors, thus bypassing some of the existing defenses.

“Given three consecutive rows A, B, and C, we were able to attack C by directing a very large number of accesses to A, along with just a handful (~dozens) to B. Based on our experiments, accesses to B have a non-linear gating effect, in which they appear to ‘transport’ the Rowhammer effect of A onto C,” the Google researchers explained.

Rowhammer Half-Double

The researchers said the Half-Double attack works against newer generation DRAM chips, but it does not work against older ones, which suggests that the shrinkage of memory cell geometries makes Rowhammer attacks “stronger and longer-ranged.” They also noted that it may be possible to launch attacks that work over distances greater than two rows.

Google has been working with JEDEC and others to come up with mitigations for Rowhammer attacks. JEDEC in March released information on system level and near-term DRAM level mitigations.

Advertisement. Scroll to continue reading.

“We are disclosing this work because we believe that it significantly advances the understanding of the Rowhammer phenomenon, and that it will help both researchers and industry partners to work together, to develop lasting solutions. The challenge is substantial and the ramifications are industry-wide,” Google researchers said.

Related: Researchers Propose Software Mitigations for Rowhammer Attacks

Related: New Rowhammer Attack Bypasses Existing Defenses

Written By

Eduard Kovacs (@EduardKovacs) is a managing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Trending

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

Join the session as we discuss the challenges and best practices for cybersecurity leaders managing cloud identities.

Register

SecurityWeek’s Ransomware Resilience and Recovery Summit helps businesses to plan, prepare, and recover from a ransomware incident.

Register

Expert Insights

Related Content

Vulnerabilities

Less than a week after announcing that it would suspended service indefinitely due to a conflict with an (at the time) unnamed security researcher...

Data Breaches

OpenAI has confirmed a ChatGPT data breach on the same day a security firm reported seeing the use of a component affected by an...

IoT Security

A group of seven security researchers have discovered numerous vulnerabilities in vehicles from 16 car makers, including bugs that allowed them to control car...

Vulnerabilities

A researcher at IOActive discovered that home security systems from SimpliSafe are plagued by a vulnerability that allows tech savvy burglars to remotely disable...

Risk Management

The supply chain threat is directly linked to attack surface management, but the supply chain must be known and understood before it can be...

Cybercrime

Patch Tuesday: Microsoft calls attention to a series of zero-day remote code execution attacks hitting its Office productivity suite.

Vulnerabilities

Patch Tuesday: Microsoft warns vulnerability (CVE-2023-23397) could lead to exploitation before an email is viewed in the Preview Pane.

Vulnerabilities

The latest Chrome update brings patches for eight vulnerabilities, including seven reported by external researchers.