Retbleed

See also: Transient execution CPU vulnerability
Retbleed
CVE identifier(s)CVE-2022-29900, CVE-2022-29901, CVE-2022-28693[dead link‍]

Retbleed is a speculative execution attack on x86-64 and ARM processors, including some recent Intel and AMD chips.[1][2] First made public in 2022, it is a variant of the Spectre vulnerability which exploits retpoline, which was a mitigation for speculative execution attacks.[3]

According to the researchers, Retbleed mitigations require extensive changes to the system which results in up to 14% and 39% performance loss on Linux for affected AMD and Intel CPU respectively.[4] The PoC works against Intel Core 6th, 7th and 8th generation microarchitectures and AMD Zen 1, Zen 1+, and Zen 2 microarchitectures.

An official document from ARM informs that all ARM CPUs affected by Spectre are also affected by Retbleed.[2]

Windows is not vulnerable because the existing mitigations already tackle it.[1] Linux kernels 5.18.14 and 5.19 contain the fixes.[5][6] The 32-bit Linux kernel, which is vulnerable, will not receive updates to fix the issue.[7]

  1. ^ a b Claburn, Thomas. "AMD, Intel chips vulnerable to 'Retbleed' Spectre variant". www.theregister.com. Retrieved 2022-07-12.
  2. ^ a b ARM Developer. "Q: Are Arm CPUs affected by the RETBLEED side-channel disclosed on the 13th July 2022?". Retrieved 2022-07-13.
  3. ^ Goodin, Dan (2022-07-12). "Intel and AMD CPUs vulnerable to a new speculative execution attack". Ars Technica. Retrieved 2022-07-12.
  4. ^ ETH Zurich Computer Security Group. "Retbleed: Arbitrary Speculative Code Execution with Return Instructions". Retrieved 2022-07-13.
  5. ^ "Stable kernels 5.18.14 and 5.15.57 [LWN.net]". lwn.net. Retrieved 2022-08-06.
  6. ^ Sharwood, Simon (2022-07-17). "Torvalds: Linux kernel team has sorted Retbleed chip flaw". www.theregister.com. Retrieved 2022-09-13.
  7. ^ Michael Larabel (2022-07-24). "Linux x86 32-bit Is Vulnerable To Retbleed But Don't Expect It To Get Fixed". phoronix.com.