CVE-2005-2728 in HTTP Server
Summary
by MITRE
The byte-range filter in Apache 2.0 before 2.0.54 allows remote attackers to cause a denial of service (memory consumption) via an HTTP header with a large Range field.
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Analysis
by VulDB Data Team • 03/12/2021
The vulnerability identified as CVE-2005-2728 represents a significant denial of service weakness in the Apache HTTP Server version 2.0.x series prior to 2.0.54. This flaw specifically targets the byte-range filter implementation within the web server's handling of HTTP requests, creating a scenario where malicious actors can exploit the system's resource management capabilities to consume excessive memory. The vulnerability manifests when an attacker crafts an HTTP request containing a malformed Range header field that specifies an excessively large range of bytes to be retrieved from a requested resource. The affected Apache versions fail to properly validate or limit the size of these range specifications, leading to uncontrolled memory allocation patterns that can quickly exhaust available system resources.
The technical mechanism behind this vulnerability involves the improper handling of HTTP Range headers in Apache's content delivery system. When a client sends a request with a Range header specifying a byte range, Apache's byte-range filter processes this information to determine which portions of a file should be returned to the client. In vulnerable versions, the server does not adequately validate the range parameters, particularly when dealing with large numerical values or malformed range specifications. This processing error results in the server allocating memory proportional to the size specified in the Range header, rather than limiting the allocation to reasonable bounds. The flaw operates at the application layer of the network stack, making it accessible through standard HTTP protocols without requiring special privileges or authentication.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire server systems. Attackers can repeatedly send crafted requests with increasingly large Range values, causing the Apache server to consume memory at an accelerating rate until system resources are exhausted. This memory exhaustion can lead to the server becoming unresponsive, rejecting legitimate requests, and potentially causing system crashes or restarts. The vulnerability is particularly dangerous in high-traffic environments where multiple simultaneous requests can compound the memory consumption effects, creating cascading failures that affect not just the targeted server but potentially the entire network infrastructure. The attack requires minimal sophistication and can be executed using standard HTTP client tools, making it accessible to attackers with basic technical knowledge.
Mitigation strategies for CVE-2005-2728 focus primarily on upgrading to Apache version 2.0.54 or later, which includes patches addressing the improper range validation logic. System administrators should also implement rate limiting and request size restrictions at network boundaries, using firewalls or proxy servers to filter out suspicious Range header values before they reach the Apache server. Additionally, monitoring systems should be configured to detect unusual memory consumption patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-131, which describes improper handling of length parameters, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing intrusion detection systems that can identify and block malformed HTTP Range headers, particularly those containing values exceeding reasonable thresholds. Regular security assessments and vulnerability scanning should include checks for this specific issue to ensure complete remediation across all web server instances.