Privilege escalation

Modern DRAM chips (DDR4 and LPDDR4 after 2015) are affected by a vulnerability in deployment of internal mitigations against RowHammer attacks known as Target Row Refresh (TRR), aka the TRRespass issue. To exploit this vulnerability, the attacker needs to create certain access patterns to trigger bit flips on affected memory modules, aka a Many-sided RowHammer attack. This means that, even when chips advertised as RowHammer-free are used, attackers may still be able to conduct privilege-escalation attacks against the kernel, conduct privilege-escalation attacks against the Sudo binary, and achieve cross-tenant virtual-machine access by corrupting RSA keys. The issue affects chips produced by SK Hynix, Micron, and Samsung. NOTE: tracking DRAM supply-chain issues is not straightforward because a single product model from a single vendor may use DRAM chips from different manufacturers.