CVE-2020-11048 in FreeRDP
Summary
by MITRE
In FreeRDP after 1.0 and before 2.0.0, there is an out-of-bounds read. It only allows to abort a session. No data extraction is possible. This has been fixed in 2.0.0.
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Analysis
by VulDB Data Team • 10/15/2020
The vulnerability identified as CVE-2020-11048 represents a critical out-of-bounds read flaw discovered in the FreeRDP remote desktop protocol implementation. This issue affects versions of FreeRDP released after version 1.0 but prior to the 2.0.0 release, creating a window of exposure for systems relying on this open-source remote desktop client library. The vulnerability manifests within the session management functionality, specifically during the abort session operation where memory access occurs beyond the bounds of allocated buffers. This type of flaw falls under the common weakness enumeration CWE-125 which describes out-of-bounds read conditions that can lead to information disclosure or application instability. The flaw is particularly concerning in remote desktop environments where FreeRDP is commonly deployed for enterprise connectivity and remote access solutions.
The technical implementation of this vulnerability stems from inadequate bounds checking within the session termination code path. When a user attempts to abort a remote desktop session, the application processes the abort request through a code sequence that fails to validate buffer boundaries before accessing memory locations. This allows an attacker who can influence the session termination process to trigger memory access violations that result in application termination or potentially more severe consequences depending on the execution environment. The vulnerability operates at the application layer within the RDP client implementation, making it exploitable through crafted session termination requests that could originate from malicious RDP servers or through network-based manipulation of session state information.
The operational impact of CVE-2020-11048 is significant despite the limitation that no data extraction occurs. The ability to abort sessions represents a denial-of-service vulnerability that can disrupt legitimate remote desktop operations and compromise business continuity. In enterprise environments where remote desktop connections are critical for system administration and user access, this vulnerability can be leveraged to disrupt services and potentially create opportunities for further attacks. The vulnerability aligns with ATT&CK technique T1499.004 which covers network disruption through session termination and can be part of broader attack chains targeting remote access infrastructure. Organizations relying on FreeRDP for remote desktop connectivity face potential service interruption risks that could affect productivity and system availability.
The mitigation strategy for this vulnerability requires immediate deployment of FreeRDP version 2.0.0 or later, which contains the necessary fixes for the out-of-bounds read condition. System administrators should prioritize patching across all environments where FreeRDP is utilized for remote desktop connections, particularly in critical infrastructure and enterprise networks. Additionally, network monitoring should be enhanced to detect unusual session termination patterns that might indicate exploitation attempts. The fix implemented in version 2.0.0 typically involves proper bounds checking mechanisms and memory validation routines that prevent access beyond allocated buffer boundaries. Organizations should also consider implementing network segmentation and access controls to limit exposure of FreeRDP components to untrusted networks, reducing the attack surface for potential exploitation of this and related vulnerabilities.