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Date: Fri, 14 Jan 2022 16:57:53 +0800
From: tr3e wang <>
Subject: Re: Linux Kernel eBPF Improper Input Validation Vulnerability

Hi all,

CVE-2022-23222 has been assigned to this issue.


tr3e wang <> 于2022年1月13日周四 16:21写道:

> Hi all,
> This vulnerability allows local attackers to escalate privileges on
> affected installations of Linux Kernel. An attacker must first obtain the
> ability to execute low-privileged code on the target system in order to
> exploit this vulnerability.
> The specific flaw exists within the handling of eBPF programs. The issue
> results from the lack of proper validation of user-supplied eBPF programs
> prior to executing them. An attacker can leverage this vulnerability to
> escalate privileges and execute code in the context of the kernel.
> BE AWARE, unprivileged bpf is disabled by default in most distros.
> *Affected Version*
>     Linux Kernel 5.8 or later
> *Root Cause Analysis*
> The bpf verifier(kernel/bpf/verifier.c) did not properly restrict several
> *_OR_NULL pointer types which allows these types to do pointer arithmetic.
> This can be leveraged to bypass the verifier check and escalate privilege.
> (see
> )
> *Exploit Code*
> Exploit code will be delayed for 5 days and will be posted at 12:00 UTC,
> Jan 18, 2022
> *Mitigations*
> set kernel.unprivileged_bpf_disabled to 1
> BE AWARE AGAIN, unprivileged bpf is disabled by default in most distros.
> *Credits*
> tr3e of SecCoder Security Lab
> Best,
> tr3e

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