CVE-2019-3930 in AM-100
Summary
by MITRE
The Crestron AM-100 firmware 1.6.0.2, Crestron AM-101 firmware 2.7.0.1, Barco wePresent WiPG-1000P firmware 2.3.0.10, Barco wePresent WiPG-1600W before firmware 2.4.1.19, Extron ShareLink 200/250 firmware 2.0.3.4, Teq AV IT WIPS710 firmware 1.1.0.7, SHARP PN-L703WA firmware 1.4.2.3, Optoma WPS-Pro firmware 1.0.0.5, Blackbox HD WPS firmware 1.0.0.5, InFocus LiteShow3 firmware 1.0.16, and InFocus LiteShow4 2.0.0.7 are vulnerable to a stack buffer overflow in libAwgCgi.so's PARSERtoCHAR function. A remote, unauthenticated attacker can use this vulnerability to execute arbitrary code as root via a crafted request to the return.cgi endpoint.
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Analysis
by VulDB Data Team • 09/11/2023
This vulnerability represents a critical stack buffer overflow flaw in multiple presentation and display management devices manufactured by Crestron, Barco, Extron, Teq, Sharp, Optoma, Blackbox, and InFocus. The vulnerability exists within the libAwgCgi.so library's PARSERtoCHAR function, which processes incoming requests through the return.cgi endpoint. The flaw allows remote attackers to manipulate memory layout by sending specially crafted requests that exceed the allocated buffer space, potentially leading to arbitrary code execution with root privileges. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a high-severity issue in the Common Weakness Enumeration catalog. The attack surface is particularly concerning given that the vulnerability is exploitable without authentication, making it accessible to any remote attacker who can reach the affected devices on their network.
The technical exploitation of this vulnerability demonstrates a classic stack buffer overflow scenario where input validation fails to properly check the length of incoming data before copying it into fixed-size buffers. When a malicious request is sent to the return.cgi endpoint, the PARSERtoCHAR function does not adequately validate the size of the data being processed, allowing an attacker to overwrite adjacent memory locations including return addresses and control registers. This memory corruption can be leveraged to redirect program execution flow and ultimately achieve remote code execution as the root user. The vulnerability's impact extends beyond simple code execution since the attacker gains full system privileges, enabling complete compromise of the affected device's functionality and potential use as a foothold for further network infiltration. According to the MITRE ATT&CK framework, this vulnerability maps to T1059.007 Command and Scripting Interpreter: Unix Shell and T1068 Exploitation for Privilege Escalation, representing both execution and privilege escalation capabilities.
The operational impact of this vulnerability is severe for organizations relying on these presentation and display management systems, as it creates an immediate risk of complete system compromise without requiring any authentication credentials. Affected devices are likely to be deployed in enterprise environments, conference rooms, control rooms, and educational facilities where they serve critical functions in managing audiovisual presentations and remote collaboration. Once exploited, attackers can use these compromised devices as pivot points for reconnaissance activities, data exfiltration, or to establish persistent access within the network infrastructure. The widespread deployment of these vulnerable devices across multiple vendors increases the potential attack surface significantly, with each compromised device representing a potential entry point for broader network compromise. Organizations using these products face the risk of unauthorized access to sensitive presentation data, disruption of critical business operations, and potential regulatory compliance violations due to unpatched security vulnerabilities.
Mitigation strategies for this vulnerability should include immediate firmware updates from the respective vendors to address the buffer overflow in the affected libAwgCgi.so library. Network segmentation should be implemented to limit access to these devices from untrusted networks, and access controls should be enforced through proper authentication mechanisms where possible. Regular vulnerability scanning and network monitoring should be deployed to identify potentially compromised devices within the network infrastructure. Organizations should also consider implementing network access control lists to restrict communication to the return.cgi endpoint and other potentially vulnerable services. Given the remote exploitability and lack of authentication requirements, administrators should treat any device running the affected firmware versions as compromised until proper patches are applied. Additionally, network administrators should monitor for unusual traffic patterns or attempts to access the return.cgi endpoint, as these activities may indicate exploitation attempts. The vulnerability highlights the importance of maintaining current firmware versions and implementing robust network security practices to prevent unauthorized access to critical infrastructure devices.