Log4j-core-2.6.1.jar Vulnerabilities Analysis And Remediation Guide

by StackCamp Team 68 views

Hey guys! Let's dive into the nitty-gritty of those pesky vulnerabilities found in log4j-core-2.6.1.jar. This guide breaks down each vulnerability, its severity, and, most importantly, how to fix it. We're talking serious stuff here, with the highest severity hitting a whopping 10.0, so buckle up and let's get started!

Understanding the Vulnerable Library

First things first, let's clarify what we're dealing with. The log4j-core-2.6.1.jar library is part of the Apache Log4j implementation, a widely-used logging framework for Java applications. You can find more details on the Apache Log4j website. This particular version has been flagged for multiple vulnerabilities, making it crucial to address them ASAP. You can usually find it nestled within your project's dependency files, like /bin/target/classes/META-INF/maven/org.whitesource/log4j-netty-sample/pom.xml.

Overview of Findings

Here’s a quick rundown of the vulnerabilities we'll be tackling. We've got a mix of critical, medium, and low-severity issues, so it's vital to get a handle on each one.

Finding Severity 🎯 CVSS Exploit Maturity EPSS Library Type Fixed in Remediation Available
CVE-2021-44228 🟣 Critical 10.0 High 94.4% log4j-core-2.6.1.jar Direct 2.12.2 ✅
CVE-2017-5645 🟣 Critical 9.8 Not Defined 94.0% log4j-core-2.6.1.jar Direct 2.8.2 ✅
CVE-2021-45046 🟣 Critical 9.0 High 94.3% log4j-core-2.6.1.jar Direct 2.12.2 ✅
CVE-2021-44832 🟠 Medium 6.6 High 53.600002% log4j-core-2.6.1.jar Direct 2.12.4 ✅
CVE-2021-45105 🟠 Medium 5.9 High 65.7% log4j-core-2.6.1.jar Direct 2.12.3 ✅
CVE-2020-9488 🟡 Low 3.7 Not Defined < 1% log4j-core-2.6.1.jar Direct ch.qos.reload4j:reload4j:1.2.18.3 ✅

Critical Vulnerabilities

CVE-2021-44228: The Big One (Severity 10.0)

This is the notorious Log4Shell vulnerability, and it's a biggie. This critical vulnerability allows for Remote Code Execution (RCE) due to improper handling of JNDI (Java Naming and Directory Interface) lookups. Basically, if an attacker can control log messages or parameters, they can execute arbitrary code by leveraging LDAP and other JNDI-related endpoints. This is super bad because it means someone could potentially take over your system just by crafting a malicious log message. The exploit maturity is high, and the EPSS (Exploit Prediction Scoring System) score is a scary 94.4%. This means it’s highly likely to be exploited.

Vulnerability Details:

  • Description: Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker-controlled LDAP and other JNDI related endpoints.
  • Publish Date: December 10, 2021
  • URL: CVE-2021-44228
  • Threat Assessment:
    • Exploit Maturity: High
    • EPSS: 94.4%
    • Score: 10.0

The Fix:

CVE-2017-5645: Deserialization of Untrusted Data (Severity 9.8)

Another critical vulnerability, CVE-2017-5645, arises from the deserialization of untrusted data. If you're using TCP or UDP socket servers to receive serialized log events, a crafted binary payload could be sent that, when deserialized, executes arbitrary code. Think of it as someone slipping a malicious package into your system that unpacks and runs without your permission. The EPSS score is a concerning 94.0%, making it a high-priority fix.

Vulnerability Details:

  • Description: 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.
  • Publish Date: April 17, 2017
  • URL: CVE-2017-5645
  • Threat Assessment:
    • Exploit Maturity: Not Defined
    • EPSS: 94.0%
    • Score: 9.8

The Fix:

CVE-2021-45046: Incomplete Fix for Log4Shell (Severity 9.0)

This critical vulnerability is like a sequel to the Log4Shell saga. It turns out the initial fix in version 2.15.0 for CVE-2021-44228 was incomplete in certain non-default configurations. Attackers with control over Thread Context Map (MDC) input data could still use JNDI lookups to execute code. It's like patching a hole in a dam, only to find another leak. With a high exploit maturity and an EPSS score of 94.3%, this one demands attention.

Vulnerability Details:

  • Description: It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data... to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments.
  • Publish Date: December 14, 2021
  • URL: CVE-2021-45046
  • Threat Assessment:
    • Exploit Maturity: High
    • EPSS: 94.3%
    • Score: 9.0

The Fix:

Medium Severity Vulnerabilities

CVE-2021-44832: JDBC Appender and JNDI LDAP Data Source (Severity 6.6)

This medium severity vulnerability affects configurations using a JDBC Appender with a JNDI LDAP data source URI. If an attacker has control over the target LDAP server, they can trigger Remote Code Execution (RCE). It's like leaving the keys to the kingdom in a visible spot. The EPSS score here is 53.600002%, indicating a moderate risk.

Vulnerability Details:

  • Description: Apache Log4j2 versions 2.0-beta7 through 2.17.0 (excluding security fix releases 2.3.2 and 2.12.4) are vulnerable to a remote code execution (RCE) attack when a configuration uses a JDBC Appender with a JNDI LDAP data source URI when an attacker has control of the target LDAP server.
  • Publish Date: December 28, 2021
  • URL: CVE-2021-44832
  • Threat Assessment:
    • Exploit Maturity: High
    • EPSS: 53.600002%
    • Score: 6.6

The Fix:

CVE-2021-45105: Uncontrolled Recursion from Self-Referential Lookups (Severity 5.9)

CVE-2021-45105, another medium severity issue, stems from uncontrolled recursion from self-referential lookups. An attacker controlling Thread Context Map data can cause a denial of service by crafting a specific string. It's like an infinite loop, but for your server. The EPSS score is 65.7%, making it a noteworthy concern.

Vulnerability Details:

  • Description: Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted.
  • Publish Date: December 18, 2021
  • URL: CVE-2021-45105
  • Threat Assessment:
    • Exploit Maturity: High
    • EPSS: 65.7%
    • Score: 5.9

The Fix:

Low Severity Vulnerability

CVE-2020-9488: Improper Validation of Certificate with Host Mismatch (Severity 3.7)

This low severity vulnerability involves improper validation of certificates with host mismatch in the Apache Log4j SMTP appender. This could allow a man-in-the-middle attack to intercept SMTPS connections, potentially leaking log messages. It's like a weak lock on a mailbox. Fortunately, the EPSS score is less than 1%, suggesting a low likelihood of exploitation.

Vulnerability Details:

  • Description: Improper validation of certificate with host mismatch in Apache Log4j SMTP appender. This could allow an SMTPS connection to be intercepted by a man-in-the-middle attack which could leak any log messages sent through that appender.
  • Publish Date: April 27, 2020
  • URL: CVE-2020-9488
  • Threat Assessment:
    • Exploit Maturity: Not Defined
    • EPSS: < 1%
    • Score: 3.7

The Fix:

  • Type: Upgrade version
  • Origin: https://reload4j.qos.ch/
  • Fix Resolution: Upgrade to ch.qos.reload4j:reload4j:1.2.18.3 or a later version.

Remediation Steps: A Summary

Okay, so we've covered a lot of ground. Here's a quick recap of the recommended fixes:

  • CVE-2021-44228: Upgrade to Log4j version 2.12.2 or later.
  • CVE-2017-5645: Upgrade to Log4j version 2.8.2 or later.
  • CVE-2021-45046: Upgrade to Log4j version 2.12.2 or later.
  • CVE-2021-44832: Upgrade to Log4j version 2.12.4 or later.
  • CVE-2021-45105: Upgrade to Log4j version 2.12.3 or later.
  • CVE-2020-9488: Upgrade to ch.qos.reload4j:reload4j:1.2.18.3 or a later version.

Upgrade your Log4j version: The most effective way to address these vulnerabilities is to upgrade to a patched version of Log4j. This typically involves updating your project's dependencies.

Verify the fix: After upgrading, thoroughly test your application to ensure the vulnerabilities are resolved and no new issues have been introduced.

Conclusion

Dealing with vulnerabilities can be a pain, but it's a necessary part of keeping our applications secure. By understanding the risks associated with log4j-core-2.6.1.jar and taking the steps to remediate them, we can significantly reduce our exposure to potential attacks. Stay vigilant, keep your libraries updated, and you'll be in a much better spot. Keep your systems updated, and you'll be in a much better spot. You got this!