CVE-2022-25167 Overview
CVE-2022-25167 is a critical remote code execution (RCE) vulnerability affecting Apache Flume versions 1.4.0 through 1.9.0. The vulnerability exists in the JMS Source component when configured to use a JNDI LDAP data source URI. An attacker who controls the target LDAP server can exploit this flaw to execute arbitrary code on the affected system, potentially leading to complete system compromise.
Critical Impact
This JNDI injection vulnerability allows unauthenticated attackers to achieve remote code execution on vulnerable Apache Flume instances when the JMS Source is configured with an attacker-controlled LDAP server URI.
Affected Products
- Apache Flume versions 1.4.0 through 1.9.0
- Systems using JMS Source with JNDI LDAP data source configuration
- Environments where attackers can influence LDAP server targets
Discovery Timeline
- 2022-06-14 - CVE-2022-25167 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2022-25167
Vulnerability Analysis
This vulnerability is a classic JNDI injection attack vector, similar to the widely publicized Log4Shell vulnerability class. When Apache Flume's JMS Source component processes configuration that includes a JNDI LDAP data source URI, it performs a JNDI lookup without properly restricting the protocols that can be used. If an attacker has control over the target LDAP server referenced in this configuration, they can serve a malicious Java object that gets deserialized and executed on the Flume server.
The vulnerability stems from improper input validation (CWE-20) where the application fails to restrict JNDI lookups to safe protocols. This allows attackers to leverage LDAP references to load and execute arbitrary Java classes from remote locations, resulting in remote code execution with the privileges of the Flume process.
Root Cause
The root cause of CVE-2022-25167 lies in the unrestricted JNDI lookup functionality within Apache Flume's JMS Source component. Prior to the fix, Flume did not limit which protocols could be used in JNDI lookups, allowing dangerous protocols like LDAP and RMI to be exploited for remote class loading. The fix addresses this by restricting JNDI to only allow the java protocol or no protocol at all, preventing attackers from using external protocols to load malicious code.
Attack Vector
The attack requires the following conditions to be met:
- The target Apache Flume instance must be configured to use a JMS Source with a JNDI LDAP data source URI
- The attacker must have control over the LDAP server referenced in the configuration, either by compromising an existing server or by manipulating the configuration to point to an attacker-controlled server
- Once the Flume instance connects to the malicious LDAP server, the attacker can return a reference to a malicious Java class that will be loaded and executed
The attack is network-based and requires no authentication or user interaction, making it highly exploitable in environments where these conditions can be satisfied. The vulnerability allows attackers to potentially gain full control of the affected system with the same privileges as the Flume service.
Detection Methods for CVE-2022-25167
Indicators of Compromise
- Unusual outbound LDAP connections from Apache Flume servers to unexpected external IP addresses
- Suspicious Java class loading activity from remote LDAP or RMI servers
- Unexpected child processes spawned by the Flume Java process
- Network connections to known malicious LDAP servers associated with JNDI exploitation campaigns
Detection Strategies
- Monitor Apache Flume configuration files for JMS Source entries with LDAP JNDI URIs pointing to untrusted servers
- Implement network monitoring to detect LDAP traffic originating from Flume servers to non-standard destinations
- Deploy endpoint detection and response (EDR) solutions capable of detecting JNDI exploitation patterns
- Review Java process behavior for anomalous class loading from external sources
Monitoring Recommendations
- Enable detailed logging for Apache Flume JMS Source connections and JNDI lookups
- Configure alerts for any LDAP connections initiated by Flume processes to external IP ranges
- Monitor for signs of post-exploitation activity such as reverse shells, credential harvesting, or lateral movement
- Implement network segmentation to limit LDAP traffic from Flume servers to only authorized directory services
How to Mitigate CVE-2022-25167
Immediate Actions Required
- Upgrade Apache Flume to version 1.10.0 or later, which includes the fix for this vulnerability
- Review all Flume configurations to identify any JMS Source components using JNDI LDAP data source URIs
- Temporarily disable or reconfigure JMS Sources that rely on LDAP JNDI lookups until patching is complete
- Implement network-level controls to restrict outbound LDAP connections from Flume servers
Patch Information
The vulnerability is fixed in Apache Flume by limiting JNDI to allow only the use of the java protocol or no protocol at all. Organizations should upgrade to Apache Flume version 1.10.0 or later. For detailed information about the fix, refer to Apache JIRA Issue FLUME-3416.
Additional resources:
Workarounds
- If immediate patching is not possible, disable JMS Source components that use JNDI LDAP URIs until the upgrade can be performed
- Implement strict network egress filtering to block outbound LDAP, LDAPS, and RMI connections from Flume servers to untrusted destinations
- Use a Web Application Firewall (WAF) or network intrusion prevention system (IPS) to detect and block JNDI exploitation attempts
- Consider isolating vulnerable Flume instances in network segments with restricted external connectivity
# Example: Network-level mitigation using iptables to block outbound LDAP
# Block outbound LDAP (port 389) and LDAPS (port 636) traffic from Flume servers
iptables -A OUTPUT -p tcp --dport 389 -m owner --uid-owner flume -j DROP
iptables -A OUTPUT -p tcp --dport 636 -m owner --uid-owner flume -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
