CVE-2023-31436
First published: Fri Apr 28 2023(Updated: )
A flaw in the Linux Kernel found. A heap out-of-bounds read vulnerability in the Linux Kernel traffic control (QoS) subsystem can be exploited to achieve local privilege escalation. The qfq_change_class function does not properly limit the lmax variable which can lead to out-of-bounds read/write. If the TCA_QFQ_LMAX value is not offered through nlattr, lmax is determined by the MTU value of the network device. The MTU of the loopback device can be set up to 2^31-1 and as a result, it is possible to have an lmax value that exceeds QFQ_MIN_LMAX. Reference: <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3037933448f60f9acb705997eae62013ecb81e0d">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3037933448f60f9acb705997eae62013ecb81e0d</a>
Credit: cve@mitre.org cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | >=3.7<4.14.314 | |
| Linux Linux kernel | >=4.15<4.19.282 | |
| Linux Linux kernel | >=4.20<5.4.242 | |
| Linux Linux kernel | >=5.5.0<5.10.179 | |
| Linux Linux kernel | >=5.11<5.15.109 | |
| Linux Linux kernel | >=5.16<6.1.26 | |
| Linux Linux kernel | >=6.2<6.2.13 | |
| IBM QRadar SIEM | <=7.5 - 7.5.0 UP8 IF01 | |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.119-1 6.11.10-1 6.12.5-1 |
Remedy
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
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Reference Links
- https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.2.13
- https://github.com/torvalds/linux/commit/3037933448f60f9acb705997eae62013ecb81e0d
- https://www.spinics.net/lists/stable-commits/msg294885.html
- https://www.debian.org/security/2023/dsa-5402
- https://lists.debian.org/debian-lts-announce/2023/06/msg00008.html
- https://security.netapp.com/advisory/ntap-20230609-0001/
- http://packetstormsecurity.com/files/173087/Kernel-Live-Patch-Security-Notice-LSN-0095-1.html
- https://launchpad.net/bugs/cve/CVE-2023-31436
- http://packetstormsecurity.com/files/173757/Kernel-Live-Patch-Security-Notice-LSN-0096-1.html
- http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3037933448f60f9acb705997eae62013ecb81e0d
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2192679
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2226780
- https://access.redhat.com/errata/RHSA-2023:6901
- https://access.redhat.com/errata/RHSA-2023:7077
- https://access.redhat.com/errata/RHSA-2024:0378
- https://access.redhat.com/errata/RHSA-2024:0412
- https://access.redhat.com/errata/RHSA-2024:0554
- https://access.redhat.com/errata/RHSA-2024:0575
- https://access.redhat.com/errata/RHSA-2024:1268
- https://access.redhat.com/errata/RHSA-2024:1269
- https://access.redhat.com/errata/RHSA-2024:1278
- https://access.redhat.com/errata/RHSA-2024:1323
- https://access.redhat.com/errata/RHSA-2024:1367
- https://access.redhat.com/errata/RHSA-2024:1377
- https://access.redhat.com/errata/RHSA-2024:1382
- https://access.redhat.com/errata/RHSA-2024:1831
- https://bugzilla.redhat.com/show_bug.cgi?id=2192671
- https://exchange.xforce.ibmcloud.com/vulnerabilities/253946
- https://www.ibm.com/support/pages/node/7150684 (Advisory)
- https://git.kernel.org/linus/3037933448f60f9acb705997eae62013ecb81e0d
- https://kernel.dance/#3037933448f60f9acb705997eae62013ecb81e0d
- https://security-tracker.debian.org/tracker/CVE-2023-31436
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-31436
- https://nvd.nist.gov/vuln/detail/CVE-2023-31436
- https://ubuntu.com/security/CVE-2023-31436
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