Exploit Development: ASLR - Coming To A KUSER_SHARED_DATA Structure Near You!

The report analyzes Windows 11’s mitigation of the longstanding KUSER_SHARED_DATA code-cave abuse by keeping the legacy static mapping at 0xfffff78000000000 read-only and introducing a randomized writable mapping (nt!MmWriteableUserSharedData) that shares the same physical page via section-backed views. Through deep kernel debugging and reverse engineering of MiProtectSharedUserPage and related memory manager routines (PTE/PFN handling, System PTE allocations), it shows how the writable view is created and how updates propagate to the read-only address, effectively raising the bar for kernel exploitation that relied on a static RW code cave.