CVE-2020-13397 in FreeRDP
Summary
by MITRE
An issue was discovered in FreeRDP before 2.1.1. An out-of-bounds (OOB) read vulnerability has been detected in security_fips_decrypt in libfreerdp/core/security.c due to an uninitialized value.
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Analysis
by VulDB Data Team • 05/19/2025
The vulnerability identified as CVE-2020-13397 represents a critical out-of-bounds read condition affecting FreeRDP versions prior to 2.1.1. This flaw resides within the security_fips_decrypt function located in the libfreerdp/core/security.c source file, making it a fundamental component of the remote desktop protocol implementation vulnerable to exploitation. The issue manifests when the function processes cryptographic operations related to FIPS (Federal Information Processing Standards) compliance, specifically during decryption routines that handle security protocols for remote desktop connections.
The technical root cause of this vulnerability stems from an uninitialized variable that is subsequently read without proper initialization before being used in memory access operations. This uninitialized value creates a scenario where the application may attempt to read data from memory locations that have not been properly set, leading to unpredictable behavior and potential information disclosure. The flaw operates at the core security layer of the FreeRDP implementation, making it particularly dangerous as it affects the fundamental cryptographic operations that protect remote desktop sessions. According to CWE classification, this represents a CWE-457: Use of Uninitialized Variable, which is a well-documented weakness that can lead to various security implications including information leakage and potential code execution.
The operational impact of CVE-2020-13397 extends beyond simple memory access violations, as it can be leveraged by remote attackers to potentially extract sensitive information from the application's memory space. When exploited, this vulnerability could allow adversaries to read uninitialized memory contents, which might contain cryptographic keys, session data, or other confidential information. The vulnerability is particularly concerning in environments where FreeRDP is used for enterprise remote desktop services, as it could provide attackers with access to credentials or other sensitive data that would normally be protected by the security protocols. This type of vulnerability aligns with ATT&CK technique T1005: Data from Local System, where adversaries may attempt to extract sensitive information from compromised systems.
Mitigation strategies for CVE-2020-13397 primarily involve immediate patching of FreeRDP installations to version 2.1.1 or later, which contains the necessary fixes for the uninitialized variable issue. Organizations should also implement network segmentation and access controls to limit exposure of FreeRDP services to untrusted networks, as recommended by security frameworks such as NIST SP 800-53. Additional protective measures include monitoring network traffic for unusual patterns that might indicate exploitation attempts, implementing intrusion detection systems, and conducting regular security assessments of remote desktop infrastructure. The vulnerability demonstrates the importance of proper variable initialization in cryptographic implementations and highlights the need for comprehensive testing of security-critical code paths. Organizations utilizing FreeRDP should also consider implementing additional security controls such as multi-factor authentication and regular security audits to reduce the overall risk profile of their remote desktop environments.