What is Rowhammer Attack?
Rowhammer Attack Definition: Flipping bits in adjacent memory cells by rapidly “hammering” certain DRAM addresses, enabling unexpected privilege escalation.
Understanding Rowhammer Attack
Rowhammer attacks exploit fundamental physical properties of modern DRAM modules, where rapidly accessing specific memory rows causes electrical interference that flips bits in adjacent rows. This hardware-level vulnerability bypasses OS-level protections, enabling attackers to potentially alter memory contents outside their permissions, leading to privilege escalation or data corruption. Although first identified in standard desktop memory, rowhammer-like effects have been shown on mobile devices and even ECC memory under certain conditions. Organizations face challenges mitigating rowhammer because software patches alone can’t fix hardware weaknesses. Hardware vendors have introduced partial defenses like Target Row Refresh (TRR), but coverage varies. Software-based approaches include limiting access to high-frequency row accesses or randomizing memory layout. Attackers might chain rowhammer with other exploits to compromise hypervisors in multi-tenant clouds or root mobile devices. Despite being known for years, rowhammer remains relevant as DRAM densities increase, making memory cells more susceptible. As a result, ongoing academic research attempts to refine detection, mitigation, and new rowhammer variants that bypass partial fixes. Overall, rowhammer underscores how low-level hardware phenomena can undermine higher-level security assumptions.