CVE-2022-40159 in JXPath
Summary
by MITRE • 10/06/2022
Those using JXPath to interpret XPath may be vulnerable to Denial of Service attacks (DOS). If the parser is running on user supplied input, an attacker may supply content that causes the parser to crash by stackoverflow. This effect may support a denial of service attack.
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Analysis
by VulDB Data Team • 10/30/2022
The vulnerability identified as CVE-2022-40159 represents a critical denial of service weakness in Apache Commons JXPath library, which is widely employed for XPath expression evaluation in Java applications. This flaw manifests when the library processes user-supplied input through its XPath parser component, creating a scenario where maliciously crafted XPath expressions can trigger stack overflow conditions. The vulnerability falls under the category of improper input validation and demonstrates how seemingly benign parsing operations can become attack vectors when inadequate safeguards are implemented. The affected systems include any application that relies on JXPath for XPath evaluation, particularly those that accept untrusted input for processing, making the impact widespread across enterprise environments.
The technical exploitation of this vulnerability occurs through the manipulation of XPath expressions that cause recursive evaluation patterns within the JXPath parser implementation. When an attacker submits specially crafted input that contains deeply nested or self-referential XPath constructs, the parser's recursive descent mechanism becomes overwhelmed, leading to stack exhaustion and subsequent application crash. This behavior aligns with CWE-674, which describes "Uncontrolled Recursion" as a vulnerability where a recursive function or parser fails to properly terminate its recursion, ultimately consuming all available stack space. The stack overflow condition typically manifests as a java.lang.StackOverflowError exception, causing the affected application to become unresponsive and requiring manual intervention to restore service availability.
The operational impact of CVE-2022-40159 extends beyond simple service disruption, as it enables attackers to systematically degrade system availability through repeated exploitation attempts. Organizations utilizing JXPath in web applications, middleware components, or any system processing user input through XPath expressions face significant risk of sustained denial of service attacks that can render critical services inaccessible. This vulnerability particularly affects applications implementing search functionality, data filtering mechanisms, or any component that processes external XPath queries, making it a prime target for adversaries seeking to disrupt business operations. The attack vector requires minimal sophistication and can be executed through automated tools, amplifying the potential damage and making it an attractive option for malicious actors.
Mitigation strategies for this vulnerability encompass multiple layers of defensive measures that should be implemented in accordance with security best practices and industry standards. The primary recommendation involves upgrading to the patched version of Apache Commons JXPath library that addresses the recursive evaluation flaw through proper recursion depth limiting and input validation. Organizations should also implement input sanitization measures that restrict the complexity and nesting levels of XPath expressions processed by the parser, effectively preventing malicious constructs from reaching the vulnerable code path. Additionally, deployment of application firewalls and web application firewalls can help detect and block suspicious XPath patterns before they reach the vulnerable parser components. The mitigation approach aligns with ATT&CK technique T1499.004, which focuses on network denial of service attacks, by implementing preventive measures that limit the effectiveness of such attacks against vulnerable applications. System monitoring should include detection of stack overflow conditions and unusual parsing patterns to enable rapid response to potential exploitation attempts.