This Metasploit module exploits a bug in io_uring leading to an additional put_cred() that can be exploited to hijack credentials of other processes. This exploit will spawn SUID programs to get the freed cred object reallocated by a privileged process and abuse them to create a SUID root binary that will pop a shell. The dangling cred pointer will, however, lead to a kernel panic as soon as the task terminates and its credentials are destroyed. We therefore detach from the controlling terminal, block all signals and rest in silence until the system shuts down and we get killed hard, just to cry in vain, seeing the kernel collapse. The bug affected kernels from v5.12-rc3 to v5.14-rc7. More than 1 CPU is required for exploitation. Successfully tested against Ubuntu 22.04.01 with kernel 5.13.12-051312-generic.
ddab5b3975fc82e2a23c5e4e05a57af4893abfbc613df02d507c1013c62dc088If the vmwgfx driver fails to copy the fence_rep object to userland, it tries to recover by deallocating the (already populated) file descriptor. This is wrong, as the fd gets released via put_unused_fd() which shouldn't be used, as the fd table slot was already populated via the previous call to fd_install(). This leaves userland with a valid fd table entry pointing to a freed file object. The authors use this bug to overwrite a SUID binary with their payload and gain root. Linux kernel versions 4.14-rc1 - 5.17-rc1 are vulnerable. Successfully tested against Ubuntu 22.04.01 with kernel 5.13.12-051312-generic.
6360a81de99a383330c5955ece5414f2f3b254143f1a5b9246e669769aa929fc
© 2022 Packet Storm. All rights reserved.
%7Cutmcsr%3D(direct)%7Cutmcmd%3D(none)){kind=small}
Follow us on Twitter
Follow us on Facebook
Subscribe to an RSS Feed