Dubbo Zookeeper does not check serialization id
CVE-2021-25641

9.8CRITICAL

Key Information:

Vendor
Apache
Status
Apache Dubbo
Vendor
CVE Published:
1 June 2021

Badges

👾 Exploit Exists🟡 Public PoC🟣 EPSS 74%

Summary

Each Apache Dubbo server will set a serialization id to tell the clients which serialization protocol it is working on. But for Dubbo versions before 2.7.8 or 2.6.9, an attacker can choose which serialization id the Provider will use by tampering with the byte preamble flags, aka, not following the server's instruction. This means that if a weak deserializer such as the Kryo and FST are somehow in code scope (e.g. if Kryo is somehow a part of a dependency), a remote unauthenticated attacker can tell the Provider to use the weak deserializer, and then proceed to exploit it.

Affected Version(s)

Apache Dubbo Apache Dubbo 2.7.x < 2.7.8

Apache Dubbo Apache Dubbo 2.6.x < 2.6.9

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2021-25641-Proof-of-Concept
Created by Dor-Tumarkin

CVE-2021-25641
Created by l0n3rs

References

https://lists.apache.org/thread.html/r99ef7fa35585d3a6876...
x_refsource_MISC

EPSS Score

74% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.