How To Scan & Fix The Log4j Vulnerability (2024)

You should also use the Java Security Manager, restrict external configuration, maintain regular updates for dependencies, and actively monitor logs and network traffic for any indications of suspicious activity using intrusion detection systems and security information and event management tools.

This powerful logging tool, despite its popularity, has been found to harbor severe security flaws that put countless systems at risk.

The impact of theLog4j vulnerability, known asCVE-2021-44228or Log4Shell, has been substantial and continues to pose a significant threat due to many unpatched systems.

Within the first 24 hours of the outbreak, security sensors recorded almost200,000 attack attempts worldwide.

In this article, we’ll explain how Log4j’s security problems work.

We’ll also give helpful tips on how to protect your applications from these threats while still enjoying the benefits of this useful logging tool.

The Log4j vulnerabilityworks by exploiting a feature within Log4j that allows log messages to include JNDI references.

Attackers craft malicious log messages containing a JNDI reference pointing to an attacker-controlled server.

When a vulnerable Log4j version processes these messages, it unwittingly triggers a remote code execution by fetching and executing malicious code hosted on the attacker’s server.

This exploit grants the attacker unauthorized access and control over the affected systems, posing a significant security risk.

The impact of this vulnerability is widespread, as Log4j is commonly used in various applications and platforms.

Due to its severity, organizations must urgently update their Log4j libraries to a patched version, implement workarounds, or apply additional security measures to mitigate the risk.

Log4j 1.x has reached its end of life, and it is no longer receiving updates or security patches.

As a result, it is highly recommended to upgrade to Log4j 2.x to ensure your applications remain secure and up-to-date.

Log4j 2.x has introduced several security enhancements, including improved handling of user input and support for various security frameworks.

These improvements are essential for mitigating potential vulnerabilities and protecting your applications.

Scanning for Log4j vulnerabilities involves several steps to ensure comprehensive detection across your systems and applications.

Here are the key steps to follow:

1. Identify potentially affected systems and applications: Create an inventory of all systems, applications, and services that use Java and might have Log4j as a dependency. This includes internal applications, third-party software, and cloud services.
2. Choose an appropriate scanning tool: Select a vulnerability scanning tool that can detect Log4j vulnerabilities, such as Nmap, Tenable Nessus, Qualys Vulnerability Management, Rapid7 InsightVM, or OpenVAS.
3. Update the scanning tool and plugins: Ensure that the scanning tool and its plugins or script libraries are up-to-date to detect the latest Log4j vulnerabilities accurately.
4. Configure the scanning tool: Configure the scanning tool to target specific systems, applications, and network segments where Log4j vulnerabilities may be present. Adjust scan settings to optimize performance and minimize the impact on system resources.
5. Run the vulnerability scan: Initiate the scanning process and monitor its progress. Scanning tools may take some time to complete, depending on the size and complexity of your network and systems.
6. Analyze the scan results: Once the scan is complete, review the results to identify any Log4j vulnerabilities. The scanning tool will typically provide detailed information about the affected systems, the specific vulnerability detected, and the associated risk level.
7. Implement remediation measures: Take the necessary steps to remediate the identified vulnerabilities, such as updating Log4j to a patched version, applying workarounds, or adjusting system configurations. Re-scan the affected systems to ensure that the vulnerabilities have been resolved.
8. Monitor and maintain: Continuously monitor your systems and applications for new Log4j-related vulnerabilities and other security threats. Regularly update your scanning tools, plugins, and system patches to maintain robust security defenses.

There are several scanning tools and methods available to detect the Log4j vulnerability in your systems and applications.

Some of these tools include:

Nmap is a widely used, open-source network scanning tool that can help identify vulnerable systems by probing open ports and services.

Nmap scripts (NSE) specific to Log4j vulnerability detection have been developed, such as log4j2-scan and log4shell.

Nessus is a popular vulnerability scanner that can detect the Log4j vulnerability using its regularly updated plugin library.

Ensure that you have the latest plugins to scan for Log4j-related issues.

Qualys offers a cloud-based vulnerability management platform that can scan your network, systems, and applications for Log4j vulnerabilities.

It provides detailed reports and remediation guidance to address the issue.

Rapid7’s vulnerability management solutions, InsightVM and Nexpose, can scan your infrastructure for Log4j vulnerabilities.

They offer real-time vulnerability data and prioritization to help you remediate the issue effectively.

OpenVAS is an open-source vulnerability scanner that can detect Log4j vulnerabilities with its up-to-date plugin feeds.

As a part of the Greenbone Vulnerability Management suite, it offers comprehensive vulnerability scanning and reporting capabilities.

In addition to these scanning tools, it is also essential to regularly review logs, employ intrusion detection systems, and monitor network traffic for any signs of Log4j exploitation.

The most effective mitigation strategy is to update the Log4j library to the latest version.

The Apache Software Foundation has released patches addressing the vulnerability:

• Log4j 2.15.0 or later for CVE-2021-44228
• Log4j 2.16.0 or later for CVE-2021-45046 (an additional vulnerability discovered during the investigation)

If updating Log4j is not immediately feasible, temporary workarounds can be implemented, such as:

• Disabling JNDI lookups by setting the system property log4j2.formatMsgNoLookups to true
• Removing the JndiLookup class from the Log4j jar file

Regularly monitor logs and network traffic to detect any signs of exploitation. Utilize intrusion detection systems (IDS) and security information and event management (SIEM) tools for real-time threat detection.

To find Log4j on Windows systems, you can use the following methods:

• File Explorer search: Open the File Explorer and navigate to the root directory of your system, applications, or services that may use Log4j as a dependency. Use the search functionality in the top-right corner and search for “log4j*.jar” to find all Log4j JAR files.
• Command Prompt search: Open the Command Prompt and navigate to the root directory where you suspect Log4j may be present. Use the following command to search for Log4j JAR files:

dir /s /b log4j*.jar

This command searches for Log4j JAR files in the current directory and all its subdirectories, displaying the results with the full path.

• PowerShell search: Open PowerShell and navigate to the root directory where you suspect Log4j may be present. Use the following command to search for Log4j JAR files:

Get-ChildItem -Path . -Recurse -Filter “log4j*.jar” -File | Select-Object FullName

This command searches for Log4j JAR files in the current directory and all its subdirectories, displaying the results with the full path.

Remember to examine all Java applications and services, including third-party software and cloud services, as they might also contain Log4j dependencies.

To prevent future Log4j-related issues, you should consider the following strategies:

• Stay informed: Regularly check for updates and news about Log4j and related vulnerabilities. Think of it as staying one step ahead of potential attackers.
• Maintain proper patch management:Keep all your software up-to-date, including libraries like Log4j. This will minimize the chances of having unpatched vulnerabilities in your environment.
• Implement continuous vulnerability management: Establish a formal process for identifying, assessing, and remediating vulnerabilities in your applications and infrastructure. A solid vulnerability management plan is like a strong shield against cyber threats.
• Invest in cyber hygiene: Adopt good cybersecurity practices, such as regular penetration tests, employee training, and endpoint security solutions. This will help reduce your overall attack surface and keep your systems protected.

Log4j is an open-source Java-based logging library that has recently gained attention due to a critical vulnerability known as Log4Shell.

This flaw allows attackers to execute arbitrary code on vulnerable systems, leading to a wide range of cybersecurity issues, such as malware infections, denial-of-service attacks, and other exploits.

Think of Log4j as a digital lock that, unfortunately, can be picked by those with malicious intent.

Anyone using the affected versions of the Log4j library is at risk, including small businesses, large enterprises, and even individuals. Windows, Linux, and macOS systems can all be affected.

This vulnerability is considered a “zero-day” exploit, meaning it was unknown until it was publicly disclosed, leaving many systems exposed to potential attacks.

It’s like discovering your house keys have been secretly copied and distributed to burglars.

Anyone using the affected versions of the Log4j library is at risk, including small businesses, large enterprises, and even individuals. Windows, Linux, and macOS systems can all be affected.

This vulnerability is considered a “zero-day” exploit, meaning it was unknown until it was publicly disclosed, leaving many systems exposed to potential attacks.

It’s like discovering your house keys have been secretly copied and distributed to burglars.