module
io_uring Same Type Object Reuse Priv Esc
| Disclosed |
|---|
| Mar 22, 2022 |
Disclosed
Mar 22, 2022
Description
This module exploits a bug in io_uring leading to an additional put_cred()
that can be exploited to hijack credentials of other processes.
We spawn SUID programs to get the free'd cred object reallocated by a
privileged process and abuse them to create a SUID root binary ourselves
that'll 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
that can be exploited to hijack credentials of other processes.
We spawn SUID programs to get the free'd cred object reallocated by a
privileged process and abuse them to create a SUID root binary ourselves
that'll 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
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