Fresh SLAM Attack Extracts Sensitive Data from AMD CPUs and Upcoming Intel Processors

Academic researchers have unveiled a novel side-channel attack named SLAM, designed to exploit hardware enhancements meant to bolster security in forthcoming CPUs from major manufacturers like Intel, AMD, and Arm. The attack aims to retrieve the root password hash from the kernel memory through a transient execution technique.

SLAM takes advantage of a memory feature allowing software to utilize untranslated address bits in 64-bit linear addresses for metadata storage. Diverse CPU vendors implement this feature differently, with Intel calling it Linear Address Masking (LAM), AMD labeling it Upper Address Ignore (UAI), and Arm referring to it as Top Byte Ignore (TBI). 

The SLAM attack, an abbreviation for Spectre based on LAM, was identified by researchers at Vrije Universiteit Amsterdam’s Systems and Network Security Group (VUSec Group). They demonstrated the attack’s viability by emulating the upcoming LAM feature from Intel on a previous-generation Ubuntu system.

According to VUSec, SLAM primarily affects future chips meeting specific criteria due to a lack of robust canonicality checks in their designs. Despite advanced hardware features like LAM, UAI, and TBI improving memory security, they introduce exploitable micro-architectural race conditions.

The attack hinges on a new transient execution technique focusing on exploiting a previously unexplored

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