PocketMine-MP 3.x (before 3.27.0) does not implement Minecraft Bedrock protocol encryption, so the server cannot verify that a connecting client possesses the private key corresponding to its login token. An attacker who captures a valid login from another player's session (for example by tricking the player into connecting to an attacker-controlled server) can replay that login to impersonate the victim and pass XBOX Live authentication until the JWT token expires (typically 2-3 days). This affects servers directly reachable over the internet that are not behind a proxy with encryption enabled.
Fixed in 4.0.0 and backported to 3.27.0.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 3
https://github.com/pmmp/PocketMine-MP/commit/d28be4eaf24a890f7ef110a51181a3d806…
disclosure@vulncheck.com
https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-h79x-98r2-g6qc
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/pocketmine-mp-before-4.0.0-authentication-…
disclosure@vulncheck.com