CVE-2018-5200 in KMPlayer
Summary
by MITRE
KMPlayer 4.2.2.15 and earlier have a Heap Based Buffer Overflow Vulnerability. It could be exploited with a crafted FLV format file. The problem is that more frame data is copied to heap memory than the size specified in the frame header. This results in a memory corruption and remote code execution.
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Analysis
by VulDB Data Team • 04/23/2020
The vulnerability identified as CVE-2018-5200 represents a critical heap-based buffer overflow flaw in KMPlayer version 4.2.2.15 and earlier. This vulnerability resides within the multimedia player's handling of Flash Video (FLV) format files, which are commonly used for web-based video streaming and media playback. The flaw manifests when the player processes a maliciously crafted FLV file that contains oversized frame data exceeding the allocated buffer size specified in the frame header structure.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within KMPlayer's FLV parser component. When the player encounters an FLV file with malformed frame headers, it fails to properly validate the frame size parameters before attempting to copy data into heap-allocated memory buffers. This fundamental flaw allows attackers to specify frame data sizes that exceed the allocated buffer boundaries, resulting in memory corruption that can be exploited for arbitrary code execution. The vulnerability specifically targets heap memory allocation patterns where the player pre-allocates buffers based on header information without sufficient bounds checking.
From an operational perspective, this vulnerability presents a significant risk to end users who may unknowingly download or receive malicious FLV files through various attack vectors including email attachments, compromised websites, or peer-to-peer networks. The remote code execution capability means that attackers can potentially gain full control over affected systems without requiring local access or user interaction beyond opening the malicious file. This makes the vulnerability particularly dangerous in enterprise environments where users may encounter such files through legitimate business processes or social engineering attacks. The exploitability of this vulnerability aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and can be classified under CWE-121 as heap-based buffer overflow.
The impact of exploitation extends beyond simple privilege escalation as the vulnerability can be leveraged for persistent system compromise through various attack chains. Security researchers have documented that successful exploitation typically results in the execution of malicious code with the privileges of the affected user account, potentially allowing attackers to install backdoors, steal sensitive data, or establish command and control channels. The vulnerability's classification under CWE-787 (Out-of-bounds Write) and its relationship to heap corruption patterns make it particularly challenging to detect and prevent through traditional security measures. Organizations should consider implementing network-based intrusion detection systems to monitor for suspicious FLV file patterns and ensure that all multimedia applications are regularly updated to address known vulnerabilities. The vulnerability also highlights the importance of input sanitization and bounds checking in multimedia processing libraries, as similar issues may exist in other players that handle the same file format without proper validation mechanisms.
Mitigation strategies should focus on immediate patching of affected KMPlayer versions and implementation of network-level controls to prevent execution of potentially malicious FLV files. System administrators should also consider deploying application whitelisting solutions that restrict execution of unauthorized multimedia players and ensure that all user endpoints are regularly updated with security patches. The vulnerability serves as a reminder of the critical importance of proper memory management in multimedia applications and the need for comprehensive security testing of file format parsers to prevent similar issues in other software components.