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Uninitialized memory access in Motoko incremental garbage collector

Moderate
eduarddfinity published GHSA-9rhg-3qf8-hrv3 Dec 9, 2024

Package

moc (OCaml)

Affected versions

>= 0.9.0, < 0.13.4

Patched versions

0.13.4

Description

Impact

Motoko's incremental garbage collector is impacted by an uninitialized memory access bug, caused by incorrect use of write barriers in a few locations. This vulnerability could potentially allow unauthorized read or write access to a Canister's memory. However, exploiting this bug requires the Canister to enable the incremental garbage collector or enhanced orthogonal persistence, which are non-default features in Motoko.

Patches

The problem has been fixed in #4677 and users are asked to upgrade to version 0.13.4. This can be done by updating to the latest dfx version (0.24.3) which includes Motoko version 0.13.4.

dfxvm install 0.24.3

Workarounds

Disable incremental garbage collector and enhanced orthogonal persistence. i.e. do not compile with —incremental-gc or --enhanced-orthogonal-persistence options.

References

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
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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:N/S:U/C:L/I:L/A:L

CVE ID

CVE-2024-11991

Weaknesses

Credits