CVE-2017-1000048 in qs Module
Summary
by MITRE
the web framework using ljharb's qs module older than v6.3.2, v6.2.3, v6.1.2, and v6.0.4 is vulnerable to a DoS. A malicious user can send a evil request to cause the web framework crash.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/12/2022
The vulnerability identified as CVE-2017-1000048 affects web applications that utilize ljharb's qs module, a popular JavaScript library for parsing and stringifying query strings. This issue represents a denial of service vulnerability that specifically impacts versions of the qs module prior to v6.3.2, v6.2.3, v6.1.2, and v6.0.4, creating a significant security risk for applications relying on this parsing functionality. The vulnerability stems from insufficient input validation and processing of malformed query parameters within the module's parsing algorithm.
The technical flaw manifests when a malicious user crafts a specially crafted request containing malformed query parameters that exploit a recursive parsing behavior within the qs module. This recursive processing creates a path where the parser can be forced into an infinite loop or consume excessive computational resources, ultimately leading to application crash or unresponsiveness. The vulnerability is classified under CWE-400 as an unchecked resource consumption, specifically involving excessive CPU or memory usage during parsing operations. The malicious input typically involves deeply nested or malformed parameter structures that cause the parser to recursively process the same data multiple times without proper termination conditions.
The operational impact of this vulnerability extends beyond simple application instability, potentially affecting service availability and user experience across affected web frameworks. When exploited, the DoS condition can cause complete service disruption, requiring manual intervention to restart affected services and potentially leading to extended downtime. This vulnerability affects a wide range of web applications including those built on Node.js frameworks such as Express.js, which commonly integrate the qs module for query string processing. The attack vector is particularly concerning because it requires minimal technical expertise to execute and can be automated, making it attractive to attackers seeking to disrupt services. From an ATT&CK perspective, this vulnerability aligns with technique T1499.004 for Network Denial of Service and T1595.001 for Network Sniffing, as it can be exploited through crafted network requests without requiring elevated privileges.
Mitigation strategies for this vulnerability require immediate version updates of the affected qs module to versions v6.3.2 or later, which contain patches addressing the recursive parsing issue. Organizations should implement comprehensive dependency management practices including regular security audits, automated vulnerability scanning, and dependency update monitoring to prevent similar issues from occurring in the future. The patch addresses the vulnerability by introducing proper recursion limits and input validation checks that prevent maliciously crafted requests from causing resource exhaustion. Additionally, implementing request rate limiting, input sanitization, and monitoring for unusual parsing patterns can provide additional defense in depth layers. Security teams should also consider implementing web application firewalls or API gateways that can detect and block suspicious query string patterns before they reach vulnerable applications. The vulnerability highlights the critical importance of keeping third-party dependencies updated and demonstrates how seemingly benign parsing functionality can become a significant security risk when not properly secured against malicious input.