CyberSecBulletin
CVE-2023-52440NVD status: Modified

Linux: Improper Restriction of Operations within the Bounds of a Memory Buffer

Published Updated By the CyberSecBulletin desk

CVE-2023-52440 is a high-severity improper restriction of operations within the bounds of a memory buffer 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 bd554ed4fdc3d38404a1c43d428432577573e809, 30fd6521b2fbd9b767e438e31945e5ea3e3a2fba, 7f1d6cb0eb6af3a8088dc24b7ddee9a9711538c4 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 22.3% chance of exploitation within 30 days, which is in the top 2.27% of all scored CVEs.

Patch this week

EPSS places it among the vulnerabilities most likely to be exploited soon.

What to do

  1. Update Linux to bd554ed4fdc3d38404a1c43d428432577573e809 or 30fd6521b2fbd9b767e438e31945e5ea3e3a2fba or 7f1d6cb0eb6af3a8088dc24b7ddee9a9711538c4 or ecd7e1c562cb08e41957fcd4b0e404de5ab38e20, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.52 or 6.4.15 or 6.5.2, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxc5049d2d73b2dc8e6bb64be633250bad1ae3d9ef up to, but not including, bd554ed4fdc3d38404a1c43d428432577573e809; f9929ef6a2a55f03aac61248c6a3a987b8546f2a up to, but not including, 30fd6521b2fbd9b767e438e31945e5ea3e3a2fba; f9929ef6a2a55f03aac61248c6a3a987b8546f2a up to, but not including, 7f1d6cb0eb6af3a8088dc24b7ddee9a9711538c4; f9929ef6a2a55f03aac61248c6a3a987b8546f2a up to, but not including, ecd7e1c562cb08e41957fcd4b0e404de5ab38e20; f9929ef6a2a55f03aac61248c6a3a987b8546f2a up to, but not including, 4b081ce0d830b684fdf967abc3696d1261387254; 5.17bd554ed4fdc3d38404a1c43d428432577573e809, 30fd6521b2fbd9b767e438e31945e5ea3e3a2fba, 7f1d6cb0eb6af3a8088dc24b7ddee9a9711538c4, ecd7e1c562cb08e41957fcd4b0e404de5ab38e20, 4b081ce0d830b684fdf967abc3696d1261387254
LinuxLinux Kernel5.17.0 up to, but not including, 6.1.52; 6.2.0 up to, but not including, 6.4.15; 6.5.0 up to, but not including, 6.5.26.1.52, 6.4.15, 6.5.2

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.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob() If authblob->SessionKey.Length is bigger than session key size(CIFS_KEY_SIZE), slub overflow can happen in key exchange codes. cifs_arc4_crypt copy to session key array from SessionKey from client.

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

The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities (CWE-119)

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 Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities

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