Saint DirtyCred, Who Swapped the Credentials

Patron of Linux kernel exploits, credential objects, and everyone who reuses memory without looking inside.

Life

In August 2022, across Black Hat and the CCS conference, Zhenpeng Lin and colleagues from Northwestern University presented DirtyCred: instead of overwriting critical kernel data, the technique abuses heap memory reuse to swap an unprivileged credential object for a privileged one. No need to defeat KASLR or leak the heap: a flaw that frees at the right moment is enough, and the process finds itself root.

Prayer

O Saint DirtyCred, who barters credentials on the same slice of memory, let our allocator never mistake a humble object for a lord. Amen.

How to celebrate

Celebrated by updating the kernel and keeping credential objects apart from the rest, so they never land in the same cache.

Reused memory, swapped privilege.