Google Researchers Discover A New Variant of Rowhammer Attack
May 26, 2021
A team of security researchers from Google has demonstrated yet another variant of the Rowhammer vulnerability that targets increasingly smaller DRAM chips to bypass all current mitigations, making it a persistent threat to chip security. Dubbed "Half-Double," the new hammering technique hinges on the weak coupling between two memory rows that are not immediately adjacent to each other but one row removed in an attempt to tamper with data stored in memory and attack a system . "Unlike TRRespass , which exploits the blind spots of manufacturer-dependent defenses, Half-Double is an intrinsic property of the underlying silicon substrate," the researchers noted . "This is likely an indication that the electrical coupling responsible for Rowhammer is a property of distance, effectively becoming stronger and longer-ranged as cell geometries shrink down. Distances greater than two are conceivable." Rowhammer attacks are similar to speculative execution