CVE-2023-3610

Published: 21 July 2023

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. Flaw in the error handling of bound chains causes a use-after-free in the abort path of NFT_MSG_NEWRULE. The vulnerability requires CAP_NET_ADMIN to be triggered. We recommend upgrading past commit 4bedf9eee016286c835e3d8fa981ddece5338795.

From the Ubuntu Security Team

It was discovered that the netfilter subsystem in the Linux kernel did not properly handle certain error conditions, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Notes

Priority reason:
By using unprivileged user namespaces, this can be exploited to achieve local privilege escalation.

Mitigation

If not needed, disable the ability for unprivileged users
to create namespaces. To do this temporarily, do:
  sudo sysctl -w kernel.unprivileged_userns_clone=0
To disable across reboots, do:
  echo kernel.unprivileged_userns_clone=0 | \
  sudo tee /etc/sysctl.d/99-disable-unpriv-userns.conf

Status

Severity score breakdown

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-3610
• https://security.googleblog.com/2023/06/learnings-from-kctf-vrps-42-linux.html
• https://ubuntu.com/security/notices/USN-6285-1
• https://ubuntu.com/security/notices/USN-6315-1
• https://ubuntu.com/security/notices/USN-6318-1
• https://ubuntu.com/security/notices/USN-6321-1
• https://ubuntu.com/security/notices/USN-6325-1
• https://ubuntu.com/security/notices/USN-6328-1
• https://ubuntu.com/security/notices/USN-6330-1
• https://ubuntu.com/security/notices/USN-6332-1
• https://ubuntu.com/security/notices/USN-6348-1
• https://ubuntu.com/security/notices/USN-6385-1
• NVD
• Launchpad
• Debian

Bugs

• https://bugzilla.redhat.com/show_bug.cgi?id=2225198
• https://bugzilla.suse.com/show_bug.cgi?id=1213580