Exploiting a textbook use-after-free security vulnerability in Chrome

In March 2020, a use-after-free (UAF) vulnerability in Chrome's WebAudio module was reported, highlighting challenges in exploiting PartitionAlloc memory allocator, which separates different types of objects for security. The vulnerability, CVE-2020-6449, involved manipulating the memory allocation of objects to achieve remote code execution (RCE) by exploiting the Fast partition. The exploitation process involved triggering a UAF condition, replacing freed objects, and using a controlled data leak to manipulate memory pointers and execute arbitrary code. The exploit demonstrates the complexities of memory management vulnerabilities and the importance of multiple layers of security, such as sandboxing, in mitigating potential threats. Despite the limited write primitive involved, the vulnerability was exploited by strategically decrementing pointer fields and aligning overlapping memory allocations, showcasing both the intricacies and potential risks of such security flaws.