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BoringSSLAEADContext in Netty Repeats Nonces

Moderate severity GitHub Reviewed Published Jun 4, 2024 in netty/netty-incubator-codec-ohttp

Package

maven io.netty.incubator:netty-incubator-codec-ohttp (Maven)

Affected versions

>= 0.0.3.Final, < 0.0.11.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.

https://github.com/netty/netty-incubator-codec-ohttp/blob/1ddadb6473cd3be5491d114431ed4c1a9f316001/codec-ohttp-hpke-classes-boringssl/src/main/java/io/netty/incubator/codec/hpke/boringssl/BoringSSLAEADContext.java#L112-L114

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.

References

@normanmaurer normanmaurer published to netty/netty-incubator-codec-ohttp Jun 4, 2024
Published by the National Vulnerability Database Jun 4, 2024
Published to the GitHub Advisory Database Jun 5, 2024
Reviewed Jun 5, 2024

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

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(61st percentile)

Weaknesses

Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number. Learn more on MITRE.

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

CVE ID

CVE-2024-36121

GHSA ID

GHSA-g762-h86w-8749

Source code

Credits

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