CVE-2024-23722 in Bit
Summary
by MITRE • 03/26/2024
In Fluent Bit 2.1.8 through 2.2.1, a NULL pointer dereference can be caused via an invalid HTTP payload with the content type of x-www-form-urlencoded. It crashes and does not restart. This could result in logs not being delivered properly.
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Analysis
by VulDB Data Team • 02/03/2025
The vulnerability identified as CVE-2024-23722 represents a critical NULL pointer dereference flaw within Fluent Bit versions 2.1.8 through 2.2.1 that specifically manifests when processing HTTP payloads with x-www-form-urlencoded content type. This issue falls under the Common Weakness Enumeration category CWE-476 which describes NULL pointer dereference conditions that can lead to application crashes and potential denial of service scenarios. The flaw occurs during the parsing and handling of malformed HTTP requests that contain form-encoded data, creating a scenario where the application attempts to access memory locations that have not been properly initialized or allocated.
The technical exploitation of this vulnerability requires an attacker to send a specially crafted HTTP request containing invalid x-www-form-urlencoded content to a Fluent Bit instance configured to accept such payloads. When the system processes this malformed data, the application's HTTP input plugin fails to properly validate the payload structure before attempting to dereference pointers that remain NULL due to the invalid input format. This results in an immediate crash of the Fluent Bit process without any graceful error handling or recovery mechanisms. The crash occurs at the application level rather than at the operating system level, making it particularly challenging to detect and remediate through traditional system monitoring approaches.
The operational impact of this vulnerability extends beyond simple application instability to potentially compromise the integrity of log collection and delivery systems that depend on Fluent Bit. When the service crashes, it ceases to forward log data to configured destinations, creating gaps in monitoring and security operations that could span from minutes to hours depending on manual intervention or automated recovery processes. This disruption directly affects the availability of critical infrastructure monitoring, incident response capabilities, and compliance reporting functions that rely on consistent log flow. The lack of automatic restart functionality means that administrators must manually intervene to restore service, potentially delaying detection of security events or system issues that would otherwise be captured through normal logging operations.
Organizations utilizing Fluent Bit for log aggregation and forwarding should immediately implement mitigations including upgrading to versions 2.2.2 or later where this vulnerability has been patched, implementing input validation controls at network boundaries to filter malformed HTTP requests before they reach the Fluent Bit instance, and establishing robust monitoring and alerting mechanisms to detect service crashes. Network segmentation and access controls should be strengthened to limit exposure of Fluent Bit instances to untrusted networks, while automated health checks and service restart policies should be configured to minimize downtime. The ATT&CK framework categorizes this vulnerability under T1499.004 for Network Denial of Service and T1566.001 for spearphishing attachments, highlighting the potential for both service disruption and initial access vectors through malicious payload delivery. Additionally, implementing proper input sanitization and error handling practices in the application code can prevent similar vulnerabilities from manifesting in other components of the logging infrastructure.