HTML5 Video Player 1.2.5 Local Buffer Overflow Vulnerability

HTML5 Video Player version 1.2.5 is susceptible to a local buffer overflow vulnerability (CVE-2019-25689). An attacker can exploit this flaw by crafting a malicious payload exceeding 997 bytes and pasting it into the “KEY CODE” field located within the Help Register dialog. Successful exploitation leads to arbitrary code execution within the context of the application, as demonstrated by spawning a calculator process. This vulnerability, discovered in 2019 but only recently published, highlights the importance of keeping software up to date and being cautious about user-supplied input, even in seemingly benign interfaces. The vulnerability has a CVSS v3.1 score of 8.4, indicating a high severity due to the potential for complete system compromise.

Attack Chain

1. Attacker identifies a vulnerable instance of HTML5 Video Player 1.2.5.
2. Attacker opens the Help Register dialog within the HTML5 Video Player.
3. Attacker prepares a malicious payload exceeding 997 bytes, designed to overwrite the buffer.
4. Attacker copies the crafted payload into the “KEY CODE” field within the Help Register dialog.
5. The application attempts to process the oversized key code, triggering the buffer overflow.
6. The overflow overwrites adjacent memory, including the instruction pointer.
7. The instruction pointer is redirected to attacker-controlled code within the payload.
8. The attacker-controlled code executes, spawning a calculator process as proof of concept, but can be any arbitrary code.

Impact

Successful exploitation of this buffer overflow vulnerability grants the attacker the ability to execute arbitrary code within the context of the affected HTML5 Video Player process. While the proof-of-concept exploit spawns a calculator, attackers could leverage this vulnerability to install malware, steal sensitive data, or pivot to other systems on the network. Due to the local nature of the attack, the impact is limited to systems where the vulnerable software is installed and the attacker has local access.

Recommendation

• Although no patch is available, consider uninstalling HTML5 Video Player 1.2.5 or restricting access to systems where it is installed to mitigate the risk of CVE-2019-25689.
• Monitor process creations for suspicious child processes spawned from the HTML5 Video Player executable using the Suspicious Child Process of HTML5 Video Player Sigma rule.
• Implement application whitelisting to prevent the execution of unauthorized code, which can help to mitigate the impact of successful exploitation.