CyberSecBulletin
CVE-2022-31053NVD status: Modified

biscuit: Improper Verification of Cryptographic Signature

Published Updated By the CyberSecBulletin desk

CVE-2022-31053 is a critical-severity improper verification of cryptographic signature vulnerability in biscuit from Biscuit-auth, 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 biscuit versions: biscuit-auth >= 1.0.0, < 2.0.0; biscuit-haskell = 0.1.1.0; com.clever-cloud.biscuit-java < 2.0.0, and others listed below. 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. Update Biscuit-go to 2.0.0 or a later version.
  2. Update Biscuit-java to 2.0.0 or a later version.
  3. Read the advisory on github.com for workarounds and exact fixed builds.
  4. 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
Biscuit-authbiscuitbiscuit-auth >= 1.0.0, < 2.0.0; biscuit-haskell = 0.1.1.0; com.clever-cloud.biscuit-java < 2.0.0; github.com/biscuit-auth/biscuit-go < 2.0Not stated
BiscuitsecBiscuit-auth1.0.0 through 1.1.0Not stated
BiscuitsecBiscuit-gobefore 2.0.02.0.0
BiscuitsecBiscuit-haskell0.1.1.0Not stated
Clever-cloudBiscuit-javabefore 2.0.02.0.0

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 3.19.8CriticalCNA (github.com)
CVSS 3.19.8CriticalNVD
CVSS 2.07.5HighNVD

Official description

Biscuit is an authentication and authorization token for microservices architectures. The Biscuit specification version 1 contains a vulnerable algorithm that allows malicious actors to forge valid Γ-signatures. Such an attack would allow an attacker to create a token with any access level. The version 2 of the specification mandates a different algorithm than gamma signatures and as such is not affected by this vulnerability. The Biscuit implementations in Rust, Haskell, Go, Java and Javascript all have published versions following the v2 specification. There are no known workarounds for this issue.

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

The underlying weakness: Improper Verification of Cryptographic Signature

The product does not verify, or incorrectly verifies, the cryptographic signature for data.

More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)

Timeline

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

References

Technical write-ups (may include proof of concept)

Recent Improper Verification of Cryptographic Signature vulnerabilities

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