CVE-2024-22211 in FreeRDP
Summary
by MITRE • 01/20/2024
FreeRDP is a set of free and open source remote desktop protocol library and clients. In affected versions an integer overflow in `freerdp_bitmap_planar_context_reset` leads to heap-buffer overflow. This affects FreeRDP based clients. FreeRDP based server implementations and proxy are not affected. A malicious server could prepare a `RDPGFX_RESET_GRAPHICS_PDU` to allocate too small buffers, possibly triggering later out of bound read/write. Data extraction over network is not possible, the buffers are used to display an image. This issue has been addressed in version 2.11.5 and 3.2.0. Users are advised to upgrade. there are no know workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 02/16/2025
The vulnerability identified as CVE-2024-22211 represents a critical integer overflow flaw within the FreeRDP library that impacts remote desktop protocol implementations. This issue specifically affects the `freerdp_bitmap_planar_context_reset` function where an integer overflow occurs during buffer allocation calculations. The vulnerability stems from improper handling of size calculations when processing graphics data, creating a scenario where malicious servers can craft specially crafted `RDPGFX_RESET_GRAPHICS_PDU` messages to allocate insufficient buffer space. The flaw exists in the version 2.x and 3.x branches of FreeRDP, with the vulnerability being addressed in releases 2.11.5 and 3.2.0 respectively.
The technical implementation of this vulnerability involves an integer overflow condition that results in heap-based buffer overflow behavior. When the `freerdp_bitmap_planar_context_reset` function processes graphics reset commands, it performs arithmetic operations on size parameters that can exceed the maximum representable value for the integer type used. This overflow condition causes subsequent buffer allocation to use a smaller size than required, leading to heap corruption when the application attempts to write data beyond the allocated memory boundaries. The flaw operates at the intersection of memory management and graphics processing within the RDP protocol stack, making it particularly dangerous for remote desktop clients that process untrusted graphics data from remote servers.
From an operational security perspective, this vulnerability creates a significant risk for FreeRDP-based client implementations that connect to potentially malicious RDP servers. The attack vector requires a compromised or malicious RDP server to prepare and transmit the specially crafted `RDPGFX_RESET_GRAPHICS_PDU` message, which then triggers the buffer overflow during graphics context reset operations. While the vulnerability does not enable data exfiltration over the network as the buffers are used for local image display operations, the heap corruption can potentially lead to arbitrary code execution or denial of service conditions. The impact is particularly severe for enterprise environments where remote desktop clients are extensively used for accessing corporate resources.
The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and CWE-121, Stack-based Buffer Overflow, representing a classic combination of integer arithmetic errors leading to memory corruption. From the MITRE ATT&CK framework perspective, this vulnerability could be leveraged in initial access or privilege escalation scenarios where attackers compromise RDP servers and use this flaw to gain unauthorized access to client systems. The vulnerability affects the RDP client implementation specifically, with the server-side components and proxy implementations remaining unaffected, suggesting the issue is localized to client-side graphics processing logic. Organizations using FreeRDP-based clients should immediately implement the security updates to version 2.11.5 or 3.2.0, as no effective workarounds exist for this particular vulnerability. The absence of known mitigations underscores the importance of timely patch deployment and the potential risk exposure for systems that remain unpatched.
The remediation strategy focuses entirely on software version upgrades as the primary mitigation approach, with no alternative workarounds available for this specific vulnerability. Security teams should prioritize patch management for FreeRDP-based systems, particularly those that connect to external or untrusted RDP servers. The vulnerability's nature as a heap-based buffer overflow with potential for arbitrary code execution makes it a high-priority target for immediate remediation. Organizations should also consider implementing network segmentation and monitoring for unusual RDP graphics protocol activity that might indicate exploitation attempts. Given the open-source nature of FreeRDP, the vulnerability was promptly addressed in the codebase, demonstrating the project's security response capabilities, but users must actively maintain their installations to prevent exploitation. The vulnerability serves as a reminder of the critical importance of proper integer overflow handling in memory management operations, particularly in security-sensitive applications that process external graphics data within network protocols.