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Potential Resource Exhaustion when handling Untrusted Messages

High
dignifiedquire published GHSA-4grw-m28r-q285 Dec 5, 2024

Package

cargo pgp (Rust)

Affected versions

< 0.14.2

Patched versions

0.14.2

Description

During a security audit, Radically Open Security discovered two vulnerabilities which allow attackers to trigger resource exhaustion vulnerabilities in rpgp by providing crafted messages. This affects general message parsing and decryption with symmetric keys.

Impact

Affected rpgp versions do not correctly set upper limits on the total reserved amount of memory when parsing long sequences of partial OpenPGP packets, which can grow to to several GiB in size. Additionally, up to 4GiB of memory is reserved for OpenPGP packets of fixed size with large length fields, even if less data is received.
Depending on existing message size restrictions and available system resources, this can cause out-of-memory conditions and crash the rpgp process or cause other system instability through memory resource exhaustion when parsing crafted messages.

Affected rpgp versions are susceptible to excessive memory allocation with values of up to 2TiB or long processing times for some decryption operations which involve the Argon2 function. An attacker can provide a valid Symmetric Key Encrypted Session Key packet (SKESK) which uses Argon2 for String-to-Key hashing with parameters that are excessive, but within specification limits of the RFC9580 OpenPGP standard. Since rpgp did not further restrict the Argon2 parameters, this can cause out-of-memory conditions and crash the rpgp process. Under some conditions, the memory resource exhaustion may trigger other system instability. Alternatively, this can make the program unresponsive via long computations. The attacker needs to trick a victim into attempting decryption, but does not require knowledge of the symmetric secret used by the victim.

There is no impact to confidentiality or integrity security properties.

Versions and Patches

The impact details on the message parsing component varies with different versions. We've confirmed some of the problematic behavior on older versions such as v0.10.0 and see all recent versions as affected in some form.

The affected Argon2 functionality was introduced with v0.12.0-alpha.1, earlier versions are not vulnerable.

The vulnerabilities have been fixed with version 0.14.2. We recommend all users to upgrade to this version.

References

The security audit was made possible by the NLnet Foundation NGI Zero Core grant program for rpgp.

Severity

High

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
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE ID

CVE-2024-53857

Weaknesses

Credits