CyberSecBulletin
CVE-2024-21495NVD status: Analyzed

github.com/greenpau/caddy-security: Use of Insufficiently Random Values

Published Updated By the CyberSecBulletin desk

CVE-2024-21495 is a critical-severity use of insufficiently random values vulnerability in github.com/greenpau/caddy-security, 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. The record lists version 1.0.42 as the first without the flaw, so updating github.com/greenpau/caddy-security to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update github.com/greenpau/caddy-security to 1.0.42 or a later version.
  2. Update caddy_security to 1.0.42 or a later version.
  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
Github.com/greenpau/caddy-securitygithub.com/greenpau/caddy-securitybefore 1.0.421.0.42
Authcrunchcaddy_securitybefore 1.0.421.0.42

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 NVD.

Scoring systemScoreSeverityScored by
CVSS 3.16.5MediumCNA (snyk.io)
CVSS 3.19.8CriticalNVD

Official description

Versions of the package github.com/greenpau/caddy-security before 1.0.42 are vulnerable to Insecure Randomness due to using an insecure random number generation library which could possibly be predicted via a brute-force search. Attackers could use the potentially predictable nonce value used for authentication purposes in the OAuth flow to conduct OAuth replay attacks. In addition, insecure randomness is used while generating multifactor authentication (MFA) secrets and creating API keys in the database package.

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

The underlying weakness: Use of Insufficiently Random Values

The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

How developers prevent this class of flaw

  • Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds. In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts. Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a random enough number.
  • Consider a PRNG that re-seeds itself as needed from high quality pseudo-random output sources, such as hardware devices.
  • Use products or modules that conform to FIPS 140-2 to avoid obvious entropy problems. Consult FIPS 140-2 Annex C (Approved Random Number Generators).

More Use of Insufficiently Random Values vulnerabilities (CWE-330)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other references

Other vulnerabilities in github.com/greenpau/caddy-security

All github.com/greenpau/caddy-security vulnerabilities

Recent Use of Insufficiently Random Values vulnerabilities

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