CVE-2016-9176 in RUMBA
Summary
by MITRE
Stack buffer overflow in the send.exe and receive.exe components of Micro Focus Rumba 9.4 and earlier could be used by local attackers or attackers able to inject arguments to these binaries to execute code.
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Analysis
by VulDB Data Team • 09/29/2022
The vulnerability identified as CVE-2016-9176 represents a critical stack buffer overflow flaw affecting Micro Focus Rumba 9.4 and earlier versions. This vulnerability specifically impacts the send.exe and receive.exe components of the software, which are integral parts of the terminal emulation solution designed for mainframe connectivity. The flaw stems from inadequate input validation within these binaries, creating a condition where maliciously crafted arguments can overwrite adjacent memory locations on the stack. The vulnerability is particularly concerning because it can be exploited by both local attackers with system access and remote attackers who can inject arguments into the vulnerable processes, expanding the attack surface significantly.
The technical implementation of this buffer overflow occurs when the send.exe and receive.exe binaries process command-line arguments without proper bounds checking. When an attacker supplies input exceeding the allocated buffer size, the excess data overflows into adjacent stack memory regions, potentially overwriting return addresses, function pointers, or other critical control data. This memory corruption can lead to arbitrary code execution with the privileges of the affected process, typically running with elevated system permissions. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which classifies this as a fundamental memory safety issue where insufficient bounds checking allows attackers to overwrite adjacent memory locations.
The operational impact of CVE-2016-9176 extends beyond simple code execution, as it provides attackers with potential persistence mechanisms within enterprise environments. Organizations utilizing Micro Focus Rumba for mainframe terminal emulation are particularly vulnerable since these components often run with elevated privileges to facilitate proper communication with mainframe systems. The attack vector allows for privilege escalation from local user accounts to system-level access, potentially enabling attackers to access sensitive mainframe data, modify critical system configurations, or establish backdoors within the enterprise network infrastructure. This vulnerability can be exploited through various methods including command injection, argument manipulation, or even social engineering to convince legitimate users to execute maliciously crafted commands.
Mitigation strategies for this vulnerability should encompass multiple layers of defense to protect against exploitation attempts. Immediate remediation involves upgrading to Micro Focus Rumba versions that have patched this vulnerability, as the vendor has released updated releases containing proper input validation and buffer management. Organizations should also implement strict input validation measures at the system level, including parameter sanitization for all command-line arguments passed to these binaries. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, ensuring that even if one component is compromised, attackers cannot easily move laterally within the network. Additionally, implementing application whitelisting policies that restrict execution of unauthorized binaries can prevent exploitation attempts. From an operational security perspective, monitoring for suspicious command-line argument patterns and implementing intrusion detection systems that can identify potential exploitation attempts should be part of the comprehensive defense strategy. The vulnerability demonstrates the importance of proper memory management practices and adheres to ATT&CK technique T1059 Command and Scripting Interpreter, where attackers leverage command-line interfaces to execute malicious code through vulnerable applications. Organizations should also conduct regular security assessments of their terminal emulation environments to identify similar vulnerabilities in other legacy applications that may be running with elevated privileges.