Intel patches yet another bug that will further lower performance on your processor
Intel has apparently just revealed another 77 vulnerabilities throughout their product stack. This includes their networking, graphics and of course, CPU lineup. The most recently revealed one is the Jump Conditional Code (JCC) erratum bug which affects Skylake and its descendants, which means all recent CPU launched since 2015 until Comet Lake. Ice Lake is not affected though probably due to the newer Sunny Cove core architecture.
The issue apparently involves the CPU’s Decoded ICache on Skylake, with unpredictable behavior instruction cross cache lines. This Decoded ICache thingy is reportedly present since Sandy Bridge but the bug is only present in Skylake, Kaby Lake, Coffee Lake, Amber Lake, Whiskey Lake and Cascade lake processors.
Installing the microcode update to patch the JCC bug will result in a 0~4% performance hit, although some workloads will apparently see more than 4% lower performance. However this time you might be able to see a bigger impact as it affects real-world workloads too.
In addition to this new bug, the MDS vulnerabilities which were revealed back in May are apparently more serious than we were led to believe previously. A new TSX Asynchronous Abort (TAA) vulnerability has just been revealed. Interestingly, this vulnerability was shared with Intel over a year ago by the researchers who discovered the flaw.
The bug reportedly allows attackers to mount a Rogue In-Flight Data Load (RIDL) attack even with the prior mitigations released in May 2019. By exploiting TAA, attackers can find out about the following information:
- Other applications
- Operating System (OS)
- System Management Mode (SMM)
- Intel Software Guard Extensions (Intel SGX) enclaves
- Virtual Machine Manager (VMM) if present
- Other guests running under the same VMM
This issue affects even more processors, including the Whiskey Lake, Cascade Lake and Coffee Lake Refresh CPUs.
Pokdepinion: I have no idea why Intel is proud that they found 67 out of the 77 bugs. THOSE ARE YOUR BUGS!