CVE-2016-5017 in Zookeeper
Summary
by MITRE
Buffer overflow in the C cli shell in Apache Zookeeper before 3.4.9 and 3.5.x before 3.5.3, when using the "cmd:" batch mode syntax, allows attackers to have unspecified impact via a long command string.
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Analysis
by VulDB Data Team • 09/28/2024
The vulnerability identified as CVE-2016-5017 represents a critical buffer overflow flaw within Apache Zookeeper's command line interface shell implementation. This issue affects versions prior to 3.4.9 and 3.5.x prior to 3.5.3, specifically when utilizing the "cmd:" batch mode syntax for executing commands. The flaw arises from insufficient input validation and bounds checking within the shell's command processing mechanism, creating a potential entry point for malicious actors to exploit the system's memory management.
The technical implementation of this vulnerability stems from the shell's failure to properly validate the length of command strings when processing batch operations through the "cmd:" syntax. When an attacker submits a command string that exceeds the allocated buffer size, the excess data overflows into adjacent memory regions, potentially corrupting critical program state or executing arbitrary code. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions. The flaw demonstrates characteristics of CWE-787, heap-based buffer overflow, when the overflow affects heap memory regions during command processing operations.
The operational impact of CVE-2016-5017 extends beyond simple denial of service scenarios, as it provides attackers with potential arbitrary code execution capabilities within the context of the Zookeeper process. Given that Apache Zookeeper serves as a critical coordination service for distributed applications, successful exploitation could result in complete system compromise, data exfiltration, or disruption of critical distributed services. The vulnerability's exploitation aligns with ATT&CK technique T1059.007, which involves command and scripting interpreter usage through command-line interfaces, potentially enabling attackers to escalate privileges or establish persistent access within the affected environment.
Mitigation strategies for this vulnerability require immediate patching of affected Apache Zookeeper installations to versions 3.4.9 or 3.5.3 and later, which contain the necessary buffer size validation and bounds checking mechanisms. Organizations should also implement network segmentation to limit access to Zookeeper services, restrict command execution permissions, and monitor for anomalous command patterns that might indicate exploitation attempts. Additional defensive measures include implementing input validation at multiple layers, configuring proper access controls, and conducting regular security assessments of distributed systems to identify similar buffer overflow vulnerabilities. The remediation process should also involve comprehensive testing to ensure that the patched version maintains expected functionality while eliminating the buffer overflow conditions that enabled exploitation.