CVE-2008-5902 in xrdp
Summary
by MITRE
Buffer overflow in the xrdp_bitmap_invalidate function in xrdp/xrdp_bitmap.c in xrdp 0.4.1 and earlier allows remote attackers to execute arbitrary code via a crafted request.
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Analysis
by VulDB Data Team • 08/04/2021
The vulnerability identified as CVE-2008-5902 represents a critical buffer overflow flaw within the xrdp remote desktop protocol implementation. This vulnerability exists in the xrdp_bitmap_invalidate function located in the xrdp/xrdp_bitmap.c source file, affecting versions 0.4.1 and earlier. The flaw manifests when the remote desktop protocol server processes incoming bitmap data requests from client connections, creating a scenario where maliciously crafted data can cause memory corruption.
The technical nature of this vulnerability stems from inadequate input validation within the bitmap handling routine. When xrdp processes bitmap invalidation requests, the xrdp_bitmap_invalidate function fails to properly bounds-check the size parameter or data length of incoming requests. This allows an attacker to send a specially crafted request containing more data than the allocated buffer can accommodate, leading to a classic stack-based buffer overflow condition. The overflow occurs because the implementation does not verify that the incoming data fits within the predetermined buffer boundaries before copying the data into memory.
From an operational perspective, this vulnerability presents a severe risk to systems running affected xrdp versions, as it enables remote code execution without requiring authentication. Attackers can exploit this flaw from any network location to send malicious requests to the vulnerable xrdp service, potentially gaining complete control over the affected system. The implications extend beyond simple privilege escalation, as successful exploitation could allow attackers to establish persistent backdoors, exfiltrate sensitive data, or use the compromised system as a launch point for further attacks within the network infrastructure.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a significant concern for organizations relying on remote desktop services. According to ATT&CK framework, this vulnerability maps to T1071.004 for application layer protocol usage and T1059.007 for command and scripting interpreter. The attack surface is particularly concerning given that xrdp is commonly used for remote administration and system management, making it a prime target for attackers seeking persistent access to enterprise networks. Organizations using this software without proper patching measures face substantial risk of compromise, especially in environments where remote access is enabled.
Mitigation strategies should prioritize immediate patching of the affected xrdp versions to the latest stable releases containing the buffer overflow fix. Network segmentation and access controls should be implemented to limit exposure of xrdp services to untrusted networks. Additional protective measures include disabling unnecessary remote desktop services, implementing network monitoring to detect anomalous bitmap data requests, and conducting regular security assessments of remote access configurations. Organizations should also consider deploying intrusion detection systems capable of identifying the specific patterns associated with this exploit, while maintaining comprehensive logging of all remote desktop protocol connections for forensic analysis purposes.