CyberSecBulletin
CVE-2024-40762NVD status: Deferred

SonicOS: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Published Updated By the CyberSecBulletin desk

CVE-2024-40762 is a critical-severity use of cryptographically weak pseudo-random number generator (PRNG) vulnerability in SonicOS from SonicWall, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected SonicOS versions: 7.1.1-7058 and older versions; 7.1.2-7019; 8.0.0-8035. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.03% chance of exploitation within 30 days, higher than 64% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of SonicOS you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on psirt.global.sonicwall.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
SonicWallSonicOS7.1.1-7058 and older versions; 7.1.2-7019; 8.0.0-8035Not stated

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
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).

Official description

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) in the SonicOS SSLVPN authentication token generator that, in certain cases, can be predicted by an attacker potentially resulting in authentication bypass.

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

The underlying weakness: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.

How developers prevent this class of flaw

  • Use functions or hardware which use a hardware-based random number generation for all crypto. This is the recommended solution. Use CyptGenRandom on Windows, or hw_rand() on Linux.

More Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) vulnerabilities (CWE-338)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in SonicOS

All SonicOS vulnerabilities

Recent Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) vulnerabilities

Spotted an error? Tell us.