Deserialization of untrusted data in JMSAppender in Apache Log4j 1.2
CVE-2021-4104

7.5HIGH

Key Information:

Vendor
Apache
Status
Apache Log4j 1.x
Vendor
CVE Published:
14 December 2021

Badges

👾 Exploit Exists🟡 Public PoC🟣 EPSS 11%

Summary

JMSAppender in Log4j 1.2 is vulnerable to deserialization of untrusted data when the attacker has write access to the Log4j configuration. The attacker can provide TopicBindingName and TopicConnectionFactoryBindingName configurations causing JMSAppender to perform JNDI requests that result in remote code execution in a similar fashion to CVE-2021-44228. Note this issue only affects Log4j 1.2 when specifically configured to use JMSAppender, which is not the default. Apache Log4j 1.2 reached end of life in August 2015. Users should upgrade to Log4j 2 as it addresses numerous other issues from the previous versions.

Affected Version(s)

Apache Log4j 1.x Apache Log4j 1.2 1.2.x

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.

log4shell_1.x
Created by cckuailong

log4j
Created by open-AIMS

References

https://www.cve.org/CVERecord?id=CVE-2021-44228
https://github.com/apache/logging-log4j2/pull/608#issueco...
https://access.redhat.com/security/cve/CVE-2021-4104

EPSS Score

11% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.