UPMEM NAILS ROWHAMMER: French Company Offers Defense Against DRAM Vulnerability

摘要

Although human memory is notoriously faulty, computer memory requires perfection. We hardly notice a few wayward synapses, but a single-bit error in DRAM can crash a program or even a whole computer. Error-correction codes (ECC) protect servers and other mission-critical systems from random "soft errors" that flip a DRAM bit cell from one to zero or vice versa, but larger errors remain a problem. In recent years, a deliberate attack called Row-Hammer is playing havoc with DRAM chips and the computers that rely on them.First documented in 2014, RowHammer deliberately flips bits by rapidly and repeatedly accessing specific DRAM rows. Although it's unable to control the flips to write malicious code into memory, it can overwhelm ECC protection, crashing the affected program or forcing the entire system to reboot. In its simplest form, RowHammer mounts a denial-of-service (DoS) attack. In more-sophisticated assaults, it can trigger a fault that gives the attacker elevated system privileges or access to another user's virtual partition on a shared server. In other words, it's potentially catastrophic.