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rPGP Potential Resource Exhaustion when handling Untrusted Messages

High severity GitHub Reviewed Published Dec 5, 2024 in rpgp/rpgp • Updated 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.

References

@dignifiedquire dignifiedquire published to rpgp/rpgp Dec 5, 2024
Published by the National Vulnerability Database Dec 5, 2024
Published to the GitHub Advisory Database Dec 5, 2024
Reviewed Dec 5, 2024
Last updated Dec 5, 2024

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 v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality None
Integrity None
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

EPSS score

0.043%
(11th percentile)

Weaknesses

CVE ID

CVE-2024-53857

GHSA ID

GHSA-4grw-m28r-q285

Source code

Credits

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