Advisory Details

May 3rd, 2021

Linux Kernel eBPF Improper Input Validation Privilege Escalation Vulnerability

ZDI-21-503
ZDI-CAN-13661

CVE ID CVE-2021-31440
CVSS SCORE 8.8, AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
AFFECTED VENDORS Linux
AFFECTED PRODUCTS Kernel
VULNERABILITY DETAILS

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 arbitrary code in the context of the kernel.

ADDITIONAL DETAILS Linux has issued an update to correct this vulnerability. More details can be found at:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=10bf4e83167cc68595b85fd73bb91e8f2c086e36
DISCLOSURE TIMELINE
  • 2021-04-23 - Vulnerability reported to vendor
  • 2021-05-03 - Coordinated public release of advisory
CREDIT Manfred Paul
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