CVE-2022-30522 in HTTP Server
Summary
by MITRE • 06/09/2022
If Apache HTTP Server 2.4.53 is configured to do transformations with mod_sed in contexts where the input to mod_sed may be very large, mod_sed may make excessively large memory allocations and trigger an abort.
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Analysis
by VulDB Data Team • 06/11/2022
The vulnerability identified as CVE-2022-30522 represents a critical memory allocation flaw within the Apache HTTP Server version 2.4.53, specifically affecting the mod_sed module when processing large input data. This issue manifests when the server is configured to perform text transformations using the sed command processing capabilities, creating a scenario where memory consumption grows exponentially beyond normal operational parameters. The vulnerability operates through the mod_sed module's handling of input streams that exceed typical processing boundaries, leading to excessive memory allocation patterns that can overwhelm system resources.
The technical implementation of this vulnerability stems from inadequate memory management within the mod_sed module's processing pipeline. When large input data is passed to the sed transformation engine, the module fails to properly limit memory allocation growth during pattern matching and text manipulation operations. This behavior creates a resource exhaustion condition where the server process attempts to allocate memory blocks that exceed available system resources, ultimately triggering an abort condition that terminates the affected process. The flaw demonstrates characteristics consistent with heap-based buffer overflows and memory allocation errors, making it particularly dangerous in production environments where resource constraints are already tight.
Operational impact of CVE-2022-30522 extends beyond simple service disruption to encompass potential denial of service scenarios that can affect entire web server operations. When exploited, this vulnerability can cause Apache processes to terminate unexpectedly, leading to service unavailability for legitimate users. The memory allocation patterns associated with this flaw can also impact system stability by consuming excessive virtual memory resources, potentially affecting other running processes on the same host system. Organizations relying on mod_sed for content filtering, URL rewriting, or text transformation operations face significant risk of operational disruption, particularly in high-traffic environments where large data processing is common.
Mitigation strategies for CVE-2022-30522 should prioritize immediate patching of affected Apache HTTP Server installations to version 2.4.54 or later, which contains the necessary memory allocation fixes. System administrators should also implement input validation controls to limit the size of data processed by mod_sed, establishing maximum file size limits and processing thresholds. Network-level protections can include implementing rate limiting and input sanitization measures to prevent large data streams from reaching vulnerable processing paths. Additionally, monitoring solutions should be deployed to detect unusual memory consumption patterns that may indicate exploitation attempts. Organizations should also consider disabling mod_sed functionality when not actively required, as this reduces attack surface and eliminates the risk associated with this specific vulnerability. The remediation process aligns with industry best practices for memory safety and should be integrated into regular security maintenance procedures to prevent similar issues from arising in future software versions. This vulnerability highlights the importance of proper resource management in web server modules and demonstrates how seemingly routine text processing functions can become critical security concerns when not properly constrained.