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PocketMine MP vulnerable to uncontrolled resource consumption via mismatched type of 'InventoryTransactionPacket'

Moderate severity GitHub Reviewed Published May 30, 2023 in pmmp/PocketMine-MP • Updated Jun 1, 2023

Package

composer pocketmine/pocketmine-mp (Composer)

Affected versions

< 4.18.0-ALPHA2

Patched versions

4.18.0-ALPHA2

Description

Impact

A "mismatch" type InventoryTransactionPacket is sent by the client to request a resync of all currently open inventories.

Since PocketMine-MP does not rate-limit these "mismatch" transactions, and the syncing of inventories is not deferred until, e.g. the end of the current tick, they can be used as a very cheap bandwidth multiplier by making the server send out many MB of data (network serialized inventory items can be very large, especially when dealing with large amounts of NBT).

This is not currently known to have been exploited in the wild.

Patches

This problem was fixed in 4.18.0-ALPHA2 by ca6d51498f12427a947467da8fcad7811418e6cc alongside the introduction of the ItemStackRequest system implementation.

Workarounds

Plugins can handle DataPacketReceiveEvent for InventoryTransactionPacket and check if the type is MismatchTransactionData. If it is, apply some kind of rate limit (e.g. max 1 per tick).

References

@dktapps dktapps published to pmmp/PocketMine-MP May 30, 2023
Published to the GitHub Advisory Database Jun 1, 2023
Reviewed Jun 1, 2023
Last updated Jun 1, 2023

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
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
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:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weaknesses

CVE ID

No known CVE

GHSA ID

GHSA-42qm-8v8m-m78c

Source code

Credits

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