CVE-2015-4935 in Tivoli Storage Manager Fastback
Summary
by MITRE
Stack-based buffer overflow in the server in IBM Tivoli Storage Manager FastBack 6.1 before 6.1.12.1 allows remote attackers to execute arbitrary code via a crafted packet, a different vulnerability than CVE-2015-4931, CVE-2015-4932, CVE-2015-4933, and CVE-2015-4934.
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Analysis
by VulDB Data Team • 06/07/2022
The vulnerability identified as CVE-2015-4935 represents a critical stack-based buffer overflow flaw within the server component of IBM Tivoli Storage Manager FastBack version 6.1 prior to 6.1.12.1. This vulnerability specifically affects the network communication handling mechanism that processes incoming packets from remote clients, creating a pathway for malicious actors to execute arbitrary code on the affected system. The flaw resides in the server's packet processing logic where insufficient input validation and bounds checking allow attackers to overflow the allocated stack buffer through carefully crafted malicious packets. This particular vulnerability distinguishes itself from related issues CVE-2015-4931 through CVE-2015-4934 by targeting a different code path within the FastBack server implementation, making it a distinct threat vector that requires separate remediation measures.
The technical exploitation of this buffer overflow vulnerability follows a classic remote code execution attack pattern where an attacker crafts a malicious packet that exceeds the allocated buffer size during server packet processing. When the server attempts to handle this oversized packet, the excess data overflows into adjacent stack memory locations, potentially overwriting critical function return addresses and control data. This memory corruption enables attackers to redirect execution flow and inject malicious code that executes with the privileges of the FastBack server process. The vulnerability's remote nature means that attackers can exploit it without requiring local system access, making it particularly dangerous in networked environments where the server is accessible to untrusted parties. According to CWE classification, this vulnerability maps to CWE-121 Stack-based Buffer Overflow, which is categorized under the broader weakness of insufficient boundary checking in memory management operations.
The operational impact of CVE-2015-4935 extends beyond simple code execution, as successful exploitation can lead to complete system compromise and unauthorized data access. Organizations running affected versions of IBM Tivoli Storage Manager FastBack face significant risks including potential data breaches, system availability disruption, and lateral movement within their network infrastructure. The vulnerability affects backup and recovery operations that are critical to business continuity, potentially allowing attackers to manipulate backup data or disable backup services entirely. From an attacker's perspective, this vulnerability provides a persistent foothold that can be leveraged for further reconnaissance and advanced persistent threat activities. The ATT&CK framework categorizes this type of vulnerability exploitation under T1203 Exploitation for Client Execution and T1059 Command and Scripting Interpreter, highlighting the potential for attackers to establish long-term access through this initial compromise vector.
Mitigation strategies for CVE-2015-4935 primarily focus on immediate patch deployment and network segmentation. Organizations should prioritize upgrading to IBM Tivoli Storage Manager FastBack version 6.1.12.1 or later, which includes the necessary code fixes to prevent the buffer overflow condition. Network administrators should implement firewall rules to restrict access to FastBack server ports from untrusted networks and consider deploying intrusion detection systems to monitor for suspicious packet patterns. Additional protective measures include implementing network segmentation to isolate the FastBack server from critical business systems, enabling application whitelisting to prevent unauthorized code execution, and conducting regular security assessments of backup infrastructure. The vulnerability also underscores the importance of maintaining current security patches and implementing robust input validation practices across all network services to prevent similar issues from arising in other components of the system architecture.