November 14, 2023 at 06:20PM
Intel has fixed a high-severity CPU vulnerability that affects modern desktop, server, mobile, and embedded CPUs, including the latest microarchitectures. The flaw, known as CVE-2023-23583, allows attackers to escalate privileges, access sensitive information, or cause denial of service. Intel recommends updating affected processors with the latest microcode and provides mitigation guidance. The vulnerability was independently discovered by multiple research teams within Google and has been named Reptar. It is related to how redundant prefixes are interpreted by the CPU and can lead to bypassing security boundaries.
Key takeaways from the meeting notes:
1. Intel has fixed a high-severity CPU vulnerability in various CPU models, including Alder Lake, Raptor Lake, and Sapphire Rapids microarchitectures.
2. The vulnerability, known as CVE-2023-23583 or ‘Redundant Prefix Issue,’ can be exploited by attackers to escalate privileges, gain access to sensitive information, or cause a denial of service.
3. The issue occurs when executing an instruction with a redundant REX prefix, leading to unpredictable system behavior, crashes, or privilege escalation.
4. Intel believes that non-malicious software is unlikely to encounter this issue, and it is expected to require the execution of arbitrary code for malicious exploitation.
5. Systems with affected processors have already received microcode updates, and users are advised to update their BIOS, system OS, and drivers to obtain the latest microcode from their OEM, OSV, and hypervisor vendors.
6. A list of Intel CPUs affected by the vulnerability and mitigation guidance is available.
7. Google researchers independently discovered the same vulnerability and referred to it as Reptar.
8. The vulnerability bypasses CPU security boundaries by exploiting how redundant prefixes are interpreted, leading to unexpected behavior and machine check exceptions.
9. This is not the first time Google researchers have discovered vulnerabilities in Intel CPUs and AMD CPUs.
10. AMD has also recently patched a vulnerability called CacheWarp, which allows for privilege escalation and remote code execution on AMD SEV-protected VMs.