CVE-2016-5228 in RUMBA
Summary
by MITRE
Stack-based buffer overflow in the PlayMacro function in ObjectXMacro.ObjectXMacro in WdMacCtl.ocx in Micro Focus Rumba 9.x before 9.3 HF 11997 and 9.4.x before 9.4 HF 12815 allows remote attackers to execute arbitrary code via a long MacroName argument. NOTE: some references mention CVE-2016-5226 but that is not a correct ID for any Rumba vulnerability.
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Analysis
by VulDB Data Team • 02/16/2025
The vulnerability identified as CVE-2016-5228 represents a critical stack-based buffer overflow flaw within the ObjectXMacro component of Micro Focus Rumba terminal emulation software. This vulnerability specifically affects versions 9.x prior to 9.3 HF 11997 and 9.4.x prior to 9.4 HF 12815, making it a significant security concern for organizations relying on legacy terminal emulation systems. The flaw manifests within the PlayMacro function of the WdMacCtl.ocx ActiveX control, which is a core component responsible for macro execution in the Rumba environment. The vulnerability's classification as a stack-based buffer overflow aligns with CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations on the program stack.
The technical exploitation of this vulnerability occurs through manipulation of the MacroName argument parameter within the PlayMacro function. When an attacker provides a sufficiently long MacroName argument, the function fails to properly validate the input length before copying it to a fixed-size stack buffer. This improper bounds checking creates an exploitable condition where the excessive input data overflows the allocated stack space, potentially overwriting return addresses, saved registers, and other critical stack data. The attack vector is remote, meaning that adversaries can trigger this vulnerability through network-based attacks without requiring local system access or user interaction. This characteristic significantly increases the attack surface and potential impact of the vulnerability.
The operational impact of CVE-2016-5228 extends beyond simple code execution capabilities, as it provides attackers with the ability to completely compromise affected systems. Successful exploitation allows remote code execution with the privileges of the user running the vulnerable application, which typically includes system-level access in terminal emulation environments. This vulnerability directly maps to ATT&CK technique T1059.007 for Windows Command and Scripting Interpreter, as attackers can leverage the compromised system to execute arbitrary commands and potentially escalate privileges. The vulnerability's presence in a widely used terminal emulation system means that organizations running affected Rumba versions face significant risk, particularly in enterprise environments where these systems handle sensitive data and critical business processes. The impact is amplified by the fact that many organizations continue to use legacy terminal emulation solutions for critical infrastructure applications.
Mitigation strategies for CVE-2016-5228 should prioritize immediate patching of affected systems to the recommended hotfix versions 9.3 HF 11997 and 9.4 HF 12815. Organizations should also implement network segmentation and access controls to limit exposure of vulnerable systems to untrusted networks. Additionally, security teams should consider disabling ActiveX controls in web browsers and implementing application whitelisting policies to prevent execution of untrusted ActiveX components. The vulnerability demonstrates the importance of proper input validation and bounds checking in software development practices, aligning with security best practices outlined in the OWASP Top Ten and NIST Cybersecurity Framework. Organizations should also conduct comprehensive vulnerability assessments to identify other potentially affected components and ensure that their security monitoring systems can detect exploitation attempts targeting similar buffer overflow vulnerabilities.