CVE-2017-2834 in FreeRDP
Summary
by MITRE
An exploitable code execution vulnerability exists in the authentication functionality of FreeRDP 2.0.0-beta1+android11. A specially crafted server response can cause an out-of-bounds write resulting in an exploitable condition. An attacker can compromise the server or use a man in the middle attack to trigger this vulnerability.
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Analysis
by VulDB Data Team • 03/07/2023
The vulnerability identified as CVE-2017-2834 represents a critical code execution flaw within the FreeRDP 2.0.0-beta1+android11 authentication mechanism. This issue manifests as an out-of-bounds write condition that can be triggered through carefully crafted server responses, fundamentally compromising the security posture of systems utilizing this remote desktop protocol implementation. The vulnerability specifically targets the authentication functionality, which serves as the primary entry point for remote desktop connections, making it particularly dangerous for enterprise environments where remote access is prevalent.
The technical implementation of this vulnerability stems from insufficient input validation within the authentication response processing code. When FreeRDP receives authentication responses from remote servers, the software fails to properly bounds-check data structures before writing to memory locations. This allows an attacker to manipulate the server response in such a way that memory corruption occurs, potentially leading to arbitrary code execution. The flaw operates at the protocol parsing level where authentication tokens and credentials are processed, making it particularly insidious as it can be exploited during legitimate connection establishment phases. According to CWE classification, this vulnerability maps to CWE-787: Out-of-bounds Write, which is categorized under the broader weakness of improper validation of bounds of a buffer.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables sophisticated attack vectors including man-in-the-middle attacks and server compromise. An attacker positioned to intercept or manipulate network traffic can craft malicious responses that trigger the out-of-bounds write condition, potentially leading to complete system compromise. The vulnerability affects the authentication phase of RDP connections, meaning that successful exploitation could allow attackers to gain unauthorized access to systems without requiring additional credentials or privileges. This makes it particularly dangerous in enterprise environments where RDP is commonly used for remote administration and access control.
Mitigation strategies for CVE-2017-2834 must address both immediate security concerns and long-term architectural improvements. Organizations should prioritize updating to patched versions of FreeRDP that resolve the bounds-checking issues in authentication response processing. Network segmentation and monitoring should be implemented to detect anomalous authentication responses that might indicate exploitation attempts. Security controls should include intrusion detection systems configured to identify malformed RDP authentication messages, as well as network monitoring for unusual traffic patterns during authentication phases. Additionally, implementing secure communication channels with certificate validation and using strong authentication mechanisms can reduce the attack surface. From an ATT&CK framework perspective, this vulnerability aligns with T1071.004: Application Layer Protocol: Remote Desktop Protocol and T1210: Exploitation of Remote Services, highlighting the need for both defensive measures and detection capabilities. The vulnerability also demonstrates the importance of input validation in security-critical code components, emphasizing the need for comprehensive code review processes and automated testing for buffer overflow conditions.