Lukas Gerlach

The issue allows unprivileged attackers to write to arbitrary physical memory locations. This is due to certain instructions in the T-Head XuanTie C910 CPU and the T-Head XuanTie C920 CPU. The estimated number of potentially affected devices worldwide is not specified. There is no information provided about real-world incidents where this issue was exploited.

The issue concerns improper or unexpected behavior of the INVD instruction in some AMD CPUs, potentially allowing an attacker with a malicious hypervisor to affect cache line write-back behavior of the CPU. This could lead to a loss of guest virtual machine (VM) memory integrity. The vulnerability, known as CacheWarp, affects AMD's Secure Encrypted Virtualization (SEV) technology, which is designed to protect against malicious hypervisors and reduce the attack surface of virtual machines by encrypting data. CacheWarp can be exploited to escalate privileges, execute remote code, and bypass authentication in virtual machines. The attack involves manipulating cache lines and exploiting the INVD instruction to alter the behavior of the CPU, potentially allowing attackers to gain control over virtual machines and access sensitive data.

A potential power side-channel vulnerability may allow an authenticated attacker to monitor the CPU power consumption as the data in a cache line changes over time, potentially resulting in a leak of sensitive information. The vulnerability, known as Collide+Power, can be exploited to obtain confidential data, such as passwords or encryption keys. It is estimated that almost all modern processors are affected, including those from AMD, ARM, and Intel. However, the vulnerability is considered difficult to exploit, and the speed of data leakage is relatively low, making it unlikely to be used for attacks on end-users. The vulnerability can be used to enhance other software side-channel attacks, such as PLATYPUS and Hertzbleed.