CyberSecBulletin
CVE-2024-46744NVD status: Modified

Linux: Improper Link Resolution Before File Access

Published Updated By the CyberSecBulletin desk

CVE-2024-46744 is a high-severity improper link resolution before file access vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions f82cb7f24032ed023fc67d26ea9bf322d8431a90, 1b9451ba6f21478a75288ea3e3fca4be35e2a438, 5c8906de98d0d7ad42ff3edf2cb6cd7e0ea658c4 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.3% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to f82cb7f24032ed023fc67d26ea9bf322d8431a90 or 1b9451ba6f21478a75288ea3e3fca4be35e2a438 or 5c8906de98d0d7ad42ff3edf2cb6cd7e0ea658c4 or 087f25b2d36adae19951114ffcbb7106ed405ebb, whichever matches your release line, or a later version.
  2. Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1.1 or a later version.
  3. Update RUGGEDCOM RST2428P to V3.2 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, f82cb7f24032ed023fc67d26ea9bf322d8431a90; 6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, 1b9451ba6f21478a75288ea3e3fca4be35e2a438; 6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, 5c8906de98d0d7ad42ff3edf2cb6cd7e0ea658c4; 6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, 087f25b2d36adae19951114ffcbb7106ed405ebb; 6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, fac5e82ab1334fc8ed6ff7183702df634bd1d93d; 6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, c3af7e460a526007e4bed1ce3623274a1a6afe5e; 6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, ef4e249971eb77ec33d74c5c3de1e2576faf6c90; 6545b246a2c815a8fcd07d58240effb6ec3481b1 up to, but not including, 810ee43d9cd245d138a2733d87a24858a23f577d; and 1 more rangesf82cb7f24032ed023fc67d26ea9bf322d8431a90, 1b9451ba6f21478a75288ea3e3fca4be35e2a438, 5c8906de98d0d7ad42ff3edf2cb6cd7e0ea658c4, 087f25b2d36adae19951114ffcbb7106ed405ebb, fac5e82ab1334fc8ed6ff7183702df634bd1d93d, c3af7e460a526007e4bed1ce3623274a1a6afe5e
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystembefore V1.1.1V1.1.1
SiemensRUGGEDCOM RST2428Pbefore V3.2V3.2
SiemensSCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 familybefore V3.2V3.2
SiemensSCALANCE XCM-/XRM-/XCH-/XRH-300 familybefore V3.2V3.2
LinuxLinux Kernelbefore 4.19.322; 4.20 up to, but not including, 5.4.284; 5.5 up to, but not including, 5.10.226; 5.11 up to, but not including, 5.15.167; 5.16 up to, but not including, 6.1.110; 6.2 up to, but not including, 6.6.51; 6.7 up to, but not including, 6.10.10; 6.114.19.322, 5.4.284, 5.10.226, 5.15.167, 6.1.110, 6.6.51

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: Squashfs: sanity check symbolic link size Syzkiller reports a "KMSAN: uninit-value in pick_link" bug. This is caused by an uninitialised page, which is ultimately caused by a corrupted symbolic link size read from disk. The reason why the corrupted symlink size causes an uninitialised page is due to the following sequence of events: 1. squashfs_read_inode() is called to read the symbolic link from disk. This assigns the corrupted value 3875536935 to inode->i_size. 2. Later squashfs_symlink_read_folio() is called, which assigns this corrupted value to the length variable, which being a signed int, overflows producing a negative number. 3. The following loop that fills in the page contents checks that the copied bytes is less than length, which being negative means the loop is skipped, producing an uninitialised page. This patch adds a sanity check which checks that the symbolic link size is not larger than expected. -- V2: fix spelling mistake.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Link Resolution Before File Access

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

How developers prevent this class of flaw

  • Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

More Improper Link Resolution Before File Access vulnerabilities (CWE-59)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Link Resolution Before File Access vulnerabilities

Spotted an error? Tell us.