CVE-2008-2391 in SubSonic
Summary
by MITRE
SubSonic allows remote attackers to bypass pagesize limits and cause a denial of service (CPU consumption) via a pageindex (aka data page number) of -1.
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Analysis
by VulDB Data Team • 11/12/2017
The vulnerability identified as CVE-2008-2391 affects the SubSonic framework, a popular open-source web application framework for .NET developers. This flaw represents a critical denial of service vulnerability that stems from improper input validation within the pagination mechanism of the framework. The vulnerability specifically manifests when the framework processes page index parameters, which are used to navigate through data sets in a paginated manner. When an attacker submits a page index value of -1, the framework fails to properly validate this input, leading to unexpected behavior that can be exploited for malicious purposes.
The technical implementation of this vulnerability exploits a fundamental flaw in how SubSonic handles pagination parameters. The framework's data access layer processes page index values without adequate bounds checking, allowing negative values to propagate through the system. When a page index of -1 is submitted, the framework attempts to calculate the appropriate data page to retrieve, but the negative value causes the system to enter an infinite loop or extremely resource-intensive calculation process. This occurs because the framework's internal algorithms for determining page boundaries and data retrieval become malformed when processing negative index values, resulting in excessive CPU consumption as the system attempts to resolve what it perceives as a valid but problematic page reference.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise system availability and resource allocation. An attacker can leverage this flaw to consume excessive CPU cycles on the affected server, potentially leading to complete system unresponsiveness or denial of service for legitimate users. The vulnerability affects any application built using SubSonic that implements pagination functionality, making it particularly dangerous in production environments where resource constraints are already tight. The attack vector is straightforward and requires minimal technical expertise, as it only necessitates sending a single HTTP request with a malformed page index parameter, making it an attractive target for automated attack tools.
This vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and relates to the broader category of input validation flaws that frequently appear in web application frameworks. The attack pattern corresponds to the ATT&CK technique T1499.004, which involves network denial of service attacks through resource exhaustion. The flaw demonstrates a classic example of how seemingly benign input parameters can be weaponized when proper validation mechanisms are absent, highlighting the importance of defensive programming practices. Organizations using SubSonic should consider implementing input sanitization at the application level and ensure that all pagination parameters are validated against expected ranges before processing. The vulnerability also underscores the need for comprehensive security testing of framework components, particularly those handling user-provided data, as these components often become attack surfaces when proper validation is missing from the core implementation.
Mitigation strategies for this vulnerability include immediate patching of affected SubSonic versions, implementing input validation at the application layer to reject negative page index values, and configuring appropriate rate limiting to prevent abuse of the pagination functionality. Additionally, organizations should consider implementing monitoring solutions that can detect unusual CPU consumption patterns that may indicate exploitation attempts. The recommended approach involves validating all pagination parameters against expected value ranges and implementing proper error handling for invalid inputs, ensuring that the system gracefully handles edge cases rather than entering resource-intensive processing loops.