Rewterz Threat Update – New Data Leak Security Flaw ‘GhostRace’ Impacts Modern CPU Architectures

Severity

High

Analysis Summary

A new data leakage exploit that targets present-day CPU architectures supporting speculative execution has been found by a team of researchers. It is a variant of the Spectre v1 (CVE-2017-5753) transient execution CPU vulnerability, dubbed GhostRace (CVE-2024-2193). The strategy mixes race conditions with speculative execution.

A branch misprediction attack can microarchitecturally bypass all common synchronization primitives implemented using conditional branches on speculative paths. This turns all architecturally race-free critical regions into Speculative Race Conditions (SRCs), which enable threat actors to leak information from the target.

Spectre is a type of side-channel attack that circumvents application isolation safeguards by reading privileged data from memory and taking advantage of branch prediction and speculative execution on contemporary CPUs. Most CPUs use speculative execution to optimize efficiency, however, Spectre attacks leverage the fact that incorrect predictions leave behind memory access or calculation traces in the processor’s caches.

Since the vulnerabilities were discovered, microprocessor architecture has been reviewed more thoroughly. As a result, four new vulnerabilities relating to hardware microarchitectures arising from transient execution were added to the MITRE Common Weakness Enumeration (CWE) program late last month (from CWE-1420 to CWE-1423). GhostRace is unique in that it uses what’s known as a Speculative Concurrent Use-After-Free (SCUAF) attack to allow an unauthenticated attacker to leverage race conditions to access the speculative executable code pathways and extract arbitrary data from the CPU.

The researchers explained, “Race conditions arise when multiple threads attempt to access a shared resource without proper synchronization, often leading to vulnerabilities such as concurrent use-after-free. To mitigate their occurrence, operating systems rely on synchronization primitives such as mutexes, spinlocks, etc.”

After responsibly disclosing the security flaw, AMD stated that its current Spectre advisory remains applicable to mitigate this vulnerability. All versions of the Xen open-source hypervisor are affected, according to its maintainers, but they don’t believe it will be a significant security risk.

The Xen Security Team has released hardening patches as a precaution, including adding a new LOCK_HARDEN mechanism on x86 comparable to the current BRANCH_HARDEN mechanism. Because of the uncertainty surrounding the potential for a Xen vulnerability and the potential impact on performance, LOCK_HARDEN is turned off by default. Nonetheless, it is believed wise to have a mitigation in place and anticipate more research in this area.

Impact

• Exposure to Sensitive Data
• Information Theft

Indicators Of Compromise

CVE

• CVE-2024-2193

Affected Vendors

Xen

Affected Products

• XenSource Xen
• AMD CPU products

Remediation

• Refer to Xen Security Advisory for patch, upgrade, or suggested workaround information.
• Implement a robust vulnerability management program to regularly scan and identify any potential vulnerabilities in your virtualization environment. Prioritize patching and remediation based on criticality and impact.
• Implement network segmentation to isolate critical systems from other less critical systems. This can help contain the impact of a potential compromise and limit lateral movement within the network.
• Follow the principle of least privilege for user accounts and ensure that only authorized personnel have administrative access. Regularly review and revoke unnecessary privileges to minimize the attack surface.
• Deploy robust security monitoring and intrusion detection systems to detect any suspicious activities or indicators of compromise. Implement real-time log analysis and alerting mechanisms to identify potential unauthorized access attempts.
• Maintain cyber hygiene by updating your anti-virus software and implementing a patch management lifecycle.