CVE-2017-5645: Log4j Deserialization Of Untrusted Data Vulnerability

Q: What is CVE-2017-5645?

CVE-2017-5645 is a security vulnerability in Log4j involving Deserialization of Untrusted Data in Log4j under CWE-502: Deserialization of Untrusted Data.

Q: Which Log4j versions are affected?

Affected versions include releases prior to 2.8.2 across affected packages: org.apache.logging.log4j:log4j, org.apache.logging.log4j:log4j-core.

Q: What version fixes CVE-2017-5645?

Upgrading to 2.8.2 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is log4j affected?

Yes, org.apache.logging.log4j:log4j is affected in releases prior to 2.8.2. Upgrade your dependency to 2.8.2 or later.

Q: Is log4j-core affected?

Yes, org.apache.logging.log4j:log4j-core is affected in releases prior to 2.8.2. Upgrade your dependency to 2.8.2 or later.

Q: What is the CVSS score of CVE-2017-5645?

CVE-2017-5645 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Q: What CWE is associated with CVE-2017-5645?

CVE-2017-5645 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).

Q: How can I check Maven dependencies for CVE-2017-5645?

Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.logging.log4j'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

CRITICAL

Advisory Identifier: GHSA-fxph-q3j8-mv87

CVSS 9.8

CWE-502

Published 2020-01-06

Advisory Summary

CVE-2017-5645 is a CRITICAL (CVSS 9.8) deserialization of untrusted data vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Log4j libraries in the Maven ecosystem. The issue involves deserialization of untrusted data in log4j. Remediation is available by upgrading affected packages to version 2.8.2.

CVE-2017-5645 at a Glance

CVE Identifier CVE-2017-5645

GHSA Identifier GHSA-fxph-q3j8-mv87

Severity CRITICAL

CVSS v3.1 Base Score 9.8

CWE Classification CWE-502: Deserialization of Untrusted Data

Affected Product Log4j

Package Ecosystem Maven

Published Date 2020-01-06

Last Updated 2022-04-01

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)

Attack Complexity Low (AC:L)

Privileges Required None (PR:N)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality High (C:H)

Integrity High (I:H)

Availability High (A:H)

How to Fix CVE-2017-5645

To remediate this vulnerability, upgrade all affected Log4j dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.apache.logging.log4j:log4j fixed: 2.8.2

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>2.8.2</version>
</dependency>

org.apache.logging.log4j:log4j-core fixed: 2.8.2

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.8.2</version>
</dependency>

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree -Dincludes=org.apache.logging.log4j

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2017-5645, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.logging.log4j

Analyze the terminal output to locate any version of Log4j in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.8.2), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.logging.log4j command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Log4j, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In Apache Log4j 2.x before 2.8.2, when using the TCP socket server or UDP socket server to receive serialized log events from another application, a specially crafted binary payload can be sent that, when deserialized, can execute arbitrary code.

CVE-2017-5645 Affected Log4j Versions

2 component(s)

Fixed Versions:

2.8.2

Product / Package	Ecosystem	Affected Versions	Fixed Version
org.apache.logging.log4j:log4j maven/org.apache.logging.log4j/log4j	Maven	≥ 2.0 < 2.8.2	2.8.2
org.apache.logging.log4j:log4j-core maven/org.apache.logging.log4j/log4j-core	Maven	≥ 2.0 < 2.8.2	2.8.2