CVE-2020-11046 in FreeRDP
Summary
by MITRE
In FreeRDP after 1.0 and before 2.0.0, there is a stream out-of-bounds seek in update_read_synchronize that could lead to a later out-of-bounds read.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/15/2020
The vulnerability identified as CVE-2020-11046 affects FreeRDP versions between 1.0 and 2.0.0, specifically within the update_read_synchronize function where a stream out-of-bounds seek occurs. This flaw represents a critical memory safety issue that can potentially lead to arbitrary code execution or system compromise. The vulnerability exists in the remote desktop protocol implementation where proper bounds checking fails during stream processing operations. FreeRDP is a widely-used open-source remote desktop protocol implementation that enables users to connect to remote systems using the RDP protocol, making this vulnerability particularly concerning for enterprise environments and remote work deployments.
The technical flaw manifests as an insufficient validation of stream boundaries during the synchronization update processing phase. When the update_read_synchronize function handles incoming stream data, it performs a seek operation without adequate bounds checking to ensure the requested position remains within valid memory limits. This allows an attacker to craft malicious RDP packets that cause the application to access memory locations beyond the allocated buffer boundaries. The vulnerability stems from a classic buffer over-read condition where the application attempts to read data beyond the intended memory allocation, potentially exposing sensitive information or allowing execution of arbitrary code. This type of flaw falls under CWE-129 Input Validation and Bounds Checking and aligns with ATT&CK technique T1059 Command and Scripting Interpreter where adversaries may leverage memory corruption vulnerabilities to execute malicious code.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can be exploited to achieve remote code execution on systems running vulnerable FreeRDP implementations. Attackers can leverage this flaw in RDP connections to gain unauthorized access to target systems, potentially escalating privileges or establishing persistent access. The vulnerability affects not only individual user sessions but also enterprise RDP servers that may be exposed to the internet, creating significant risk for organizations relying on remote desktop infrastructure. Security researchers have noted that this type of out-of-bounds read vulnerability is particularly dangerous because it can lead to information disclosure, system crashes, or more severe exploitation opportunities depending on the memory layout and system configuration. The vulnerability's impact is amplified in environments where FreeRDP is used as a server component for remote desktop services or as part of larger remote access solutions. Organizations using FreeRDP in production environments should consider immediate remediation through version upgrades to 2.0.0 or later, as well as network segmentation and monitoring to detect potential exploitation attempts. Additionally, implementing proper input validation and bounds checking mechanisms in the affected code sections can help mitigate similar vulnerabilities in other components of the remote desktop infrastructure.