New Crosstalk vulnerability can make Intel CPUs leak data from across CPU cores

New Crosstalk vulnerability can make Intel CPUs leak data from across CPU cores

New Crosstalk vulnerability can make Intel CPUs leak data from across CPU cores  

Today’s not a good day for Intel, as a new vulnerability called “CrossTalk” has just been disclosed, impacting processors as new as Intel’s 9th Generation Coffee Lake series of CPUs.  

CrossTalk, which is also known as Special Register Buffer Data Sampling (SRBDS), was discovered back in September 2018 and has taken 21 months to patch. The exploit is a new side-channel attack which allows attackers to leak sensitive data across the cores on Intel processors, something which makes this exploit more dangerous than other recently revealed vulnerabilities. 

SRBDS cannot be fixed by restricting software to specific cores or disabling features like Hyperthreading, CrossTalk doesn’t work like that. This vulnerability exploits instructions which can perform off-core data access to shared buffers, and researchers have found that this exploit can even uncover data from Intel SGX enclaves on separate processors. 

Intel has released its own rundown on the exploit and had released a long list of affected processors. Microcode updates for Intel’s Haswell to Coffee Lake processors have also been released, though at this time it is unknown if these fixes will impact system performance. 

New Crosstalk vulnerability can make Intel CPUs leak data from across CPU cores

Thankfully, Intel’s new 10th Generation Comet Lake processors are unaffected by this exploit, and Intel’s Xeon Scalable processor families (both the Skylike and Cascade Lake variants) are similarly unimpacted. 

Intel’s mitigations for CrossTalk involves securing the processor’s memory bus before its staging buffer is updated and unlocking it once its data can be cleared. This is an expensive process, so Intel has only enabled this fix for critical security instructions. These include RDRAND, RDSEEED and EGETKEY. Intel believes that CrossTalk is difficult to exploit during real-world use cases, and are content that their mitigations are adequate. 

The good news for Intel is that this exploit only impacts the company’s older product lines, as Comet Lake, Ice Lake and Cascade Lake are unaffected. Even so, this is yet another flaw that has been uncovered for Intel processors, and that’s not good for the company’s image. 
 

A detailed write up on Intel’s CrossTalk Vulnerability is available to read here. 

You can join the discussion on Intel’s processors being impacted by a new vulnerability called “CrossTalk” on the OC3D Forums.Â