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BoringSSLAEADContext in Netty Repeats Nonces

Moderate
normanmaurer published GHSA-g762-h86w-8749 Jun 4, 2024

Package

netty-incubator-codec-ohttp (Java)

Affected versions

0.0.3.Final to 0.0.10.Final

Patched versions

0.0.11.Final

Description

Summary

BoringSSLAEADContext keeps track of how many OHTTP responses have been sent and uses this sequence number to calculate the appropriate nonce to use with the encryption algorithm.
Unfortunately, two separate errors combine which would allow an attacker to cause the sequence number to overflow and thus the nonce to repeat.

Details

  1. There is no overflow detection or enforcement of the maximum sequence value. (This is a missed requirement from the draft Chunked Oblivious OHTTP RFC and so should be inherited from the HPKE RFC 9180, Section 5.2).
  2. The sequence number (seq) is stored as 32-bit int which is relatively easy to overflow.

Impact

If the BoringSSLAEADContext is used to encrypt more than 2^32 messages then the AES-GCM nonce will repeat.
Repeating a nonce with AES-GCM results in both confidentiality and integrity compromise of data encrypted with the associated key.

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N

CVE ID

CVE-2024-36121

Credits