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Crash with incorrect JSON structures in `LoginPacket` due to dependency bug

High
dktapps published GHSA-pqp3-8rrw-g8vm May 30, 2023

Package

composer pocketmine/pocketmine-mp (Composer)

Affected versions

< 4.20.5, < 4.21.1

Patched versions

4.20.5, 4.21.1

Description

Impact

An attacker could crash PocketMine-MP by sending malformed JSON in LoginPacket.

This happened due to a bug in netresearch/jsonmapper. The library wasn't doing proper checks when mapping JSON arrays and objects onto scalar model properties such as strings.

Patches

The problem was fixed in a fork of JsonMapper in pmmp/netresearch-jsonmapper@a31902a. PocketMine-MP releases 4.20.5 and 4.21.1 have been released with the fix.

Workarounds

  • Users of PocketMine-MP source installations may manually install the patched version of JsonMapper by backporting commit 09668a3.
  • A plugin may also be able to workaround this issue by using DataPacketReceiveEvent to attempt detection of suspicious payloads. An ErrorException will be thrown in the crash case, which can be caught by plugins.

References

cweiske/jsonmapper#210

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

No known CVE

Weaknesses

No CWEs

Credits