CVE-2018-20433 in c2p0
Summary
by MITRE
c3p0 0.9.5.2 allows XXE in extractXmlConfigFromInputStream in com/mchange/v2/c3p0/cfg/C3P0ConfigXmlUtils.java during initialization.
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Analysis
by VulDB Data Team • 06/20/2023
The vulnerability identified as CVE-2018-20433 resides within the c3p0 connection pooling library version 0.9.5.2, specifically within the extractXmlConfigFromInputStream method located in com/mchange/v2/c3p0/cfg/C3P0ConfigXmlUtils.java. This flaw represents a classic XML External Entity (XXE) vulnerability that occurs during the library's initialization phase when processing XML configuration files. The vulnerability stems from the library's improper handling of XML input streams, allowing malicious actors to inject external entity references that can be resolved during parsing operations.
The technical implementation of this vulnerability involves the library's XML parser configuration which fails to disable external entity resolution and XML external general declarations. When c3p0 attempts to extract configuration data from an XML input stream, it utilizes an XML parser that does not properly restrict access to external resources. This creates an attack surface where an attacker can craft malicious XML content containing references to external entities, potentially enabling them to read local files, perform server-side request forgery attacks, or even execute denial of service operations against the targeted system. The vulnerability is particularly concerning because it occurs during library initialization, meaning any application using c3p0 that processes untrusted XML configuration data becomes immediately vulnerable.
The operational impact of CVE-2018-20433 extends beyond simple data exposure, as it can enable attackers to perform reconnaissance activities against the underlying system infrastructure. An attacker could leverage this vulnerability to access sensitive configuration files, system files, or even internal network resources that are normally protected from external access. The vulnerability affects applications that utilize c3p0 for database connection pooling and rely on XML-based configuration mechanisms. This includes enterprise applications, web services, and any system where c3p0 is used to manage database connections and where XML configuration files might be processed from untrusted sources. The attack vector is particularly dangerous because it requires no specialized privileges beyond access to the application's configuration processing capabilities, making it an attractive target for both casual attackers and more sophisticated threat actors.
Mitigation strategies for this vulnerability primarily involve upgrading to a patched version of the c3p0 library where the XML parsing behavior has been corrected to disable external entity resolution. Organizations should also implement strict input validation for any XML configuration data processed by applications using c3p0, ensuring that all XML input is from trusted sources and properly sanitized before processing. Security practitioners should consider implementing network-level restrictions that prevent outbound connections to internal resources from applications that process XML configuration data. Additionally, following the principle of least privilege and ensuring that the c3p0 library operates with minimal required permissions can help reduce the potential impact of successful exploitation attempts. This vulnerability aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and maps to ATT&CK technique T1059.007 (Command and Scripting Interpreter: PowerShell) when considering the potential for command execution through file read operations, though the primary impact is information disclosure and potential system compromise through unauthorized file access.