Downfall attacks targets a critical weakness found in billions of modern processors used in personal and cloud computers. This vulnerability, identified as CVE-2022-40982, enables a user to access and steal data from other users who share the same computer. For instance, a malicious app obtained from an app store could use the Downfall attack to steal sensitive information like passwords, encryption keys, and private data such as banking details, personal emails, and messages. Similarly, in cloud computing environments, a malicious customer could exploit the Downfall vulnerability to steal data and credentials from other customers who share the same cloud computer.

The vulnerability is caused by memory optimization features in Intel processors that unintentionally reveal internal hardware registers to software. This allows untrusted software to access data stored by other programs, which should not be normally be accessible. I discovered that the Gather instruction, meant to speed up accessing scattered data in memory, leaks the content of the internal vector register file during speculative execution. To exploit this vulnerability, I introduced Gather Data Sampling (GDS) and Gather Value Injection (GVI) techniques. You can read the paper I wrote about this for more detail. Please cite as follow:

By Daniel Moghimi