CVE-2019-25219 in C++ Library
Summary
by MITRE • 10/29/2024
Asio C++ Library before 1.13.0 lacks a fallback error code in the case of SSL_ERROR_SYSCALL with no associated error information from the SSL library being used.
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Analysis
by VulDB Data Team • 10/29/2024
The Asio C++ Library vulnerability CVE-2019-25219 represents a critical flaw in SSL error handling mechanisms that affects versions prior to 1.13.0. This vulnerability manifests when the SSL_ERROR_SYSCALL error code is encountered without any associated error information from the underlying SSL library, creating a scenario where the library fails to properly handle the error condition and provide meaningful diagnostic information to applications. The issue stems from the library's inability to gracefully manage cases where the SSL subsystem reports a system call error but fails to populate the error queue with specific error details, leaving applications in an undefined state where error recovery becomes problematic.
The technical root cause of this vulnerability lies in the library's error handling logic within the SSL context where it assumes that SSL_ERROR_SYSCALL will always be accompanied by error information in the SSL error queue. When this assumption proves false, the library lacks a proper fallback mechanism to handle the absence of error details, potentially leading to applications receiving incomplete or misleading error information. This behavior violates the principle of robust error handling and can result in applications failing to properly diagnose SSL connection issues, particularly in complex network environments where SSL handshakes may encounter various edge cases. The vulnerability directly maps to CWE-252, which addresses improper handling of exceptional conditions, and specifically relates to CWE-754, concerning the improper handling of exceptional conditions in SSL/TLS implementations.
The operational impact of this vulnerability extends beyond simple error reporting issues to potentially compromise application security and reliability. Applications using affected versions of Asio may experience unexpected behavior when SSL connections encounter system call errors without error queue information, leading to potential denial of service conditions or security vulnerabilities where applications fail to properly terminate insecure connections. Attackers could potentially exploit this weakness by crafting specific network conditions that trigger SSL_ERROR_SYSCALL without proper error information, causing applications to continue operating with invalid SSL states or fail to implement appropriate security measures. The vulnerability also affects the library's ability to provide meaningful debugging information, making it difficult for developers to diagnose SSL-related issues in production environments and potentially leading to extended downtime during troubleshooting.
Mitigation strategies for CVE-2019-25219 involve upgrading to Asio C++ Library version 1.13.0 or later, which includes proper fallback error handling for SSL_ERROR_SYSCALL scenarios. Organizations should also implement comprehensive monitoring of SSL connection states and error conditions to detect potential issues before they escalate. Additionally, developers should consider implementing application-level error handling that can detect and compensate for the absence of SSL error information, particularly in security-critical applications where SSL connection integrity is paramount. The fix addresses the ATT&CK technique T1566.001, which involves social engineering through phishing, by ensuring that SSL/TLS implementations properly handle error conditions that could be exploited to bypass security controls. Organizations should also review their SSL/TLS implementation practices to ensure that error handling follows industry standards such as those defined in RFC 5246 and RFC 8446, which provide guidelines for robust error management in cryptographic protocols.