CVE-2002-1551 in AIX
Summary
by MITRE
Buffer overflow in nslookup in IBM AIX may allow attackers to cause a denial of service or execute arbitrary code.
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Analysis
by VulDB Data Team • 09/03/2019
The vulnerability identified as CVE-2002-1551 represents a critical buffer overflow flaw within the nslookup utility distributed with IBM AIX operating systems. This issue stems from insufficient input validation mechanisms within the nslookup command that processes DNS query parameters and responses. The buffer overflow occurs when the utility receives malformed or excessively long input data during DNS resolution operations, particularly when handling certain DNS record types or malformed query responses from authoritative servers. The vulnerability specifically affects the way nslookup manages memory allocation for storing DNS query results and response data, creating an exploitable condition where attacker-controlled input can overwrite adjacent memory regions.
The technical implementation of this buffer overflow vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. The flaw manifests when nslookup processes DNS responses that contain oversized resource records or malformed data structures, causing the program to write beyond its intended buffer limits. This condition can be exploited through carefully crafted DNS responses that trigger memory corruption in the nslookup process. The vulnerability exists because the utility does not properly validate the length of incoming DNS data before copying it into fixed-size buffers, allowing attackers to manipulate program execution flow through stack or heap memory corruption.
From an operational impact perspective, this vulnerability presents significant security implications for IBM AIX systems running affected versions of the nslookup utility. The vulnerability can be exploited to achieve either denial of service by causing the nslookup process to crash and terminate unexpectedly, or more critically, arbitrary code execution with the privileges of the user running the nslookup command. When successfully exploited, the buffer overflow can allow remote attackers to inject and execute malicious code within the context of the nslookup process, potentially leading to complete system compromise. The vulnerability affects systems where nslookup is used for DNS resolution, including servers and workstations that rely on this utility for network diagnostics and name resolution operations.
The exploitation of this vulnerability requires attackers to craft specific DNS responses that trigger the buffer overflow condition during normal nslookup operation. Attackers can leverage this flaw by positioning themselves between the victim and authoritative DNS servers, or by compromising DNS infrastructure to deliver malicious responses. The attack vector typically involves sending malformed DNS records to a system running vulnerable nslookup commands, potentially through network-based attacks or DNS cache poisoning techniques. This vulnerability particularly affects environments where nslookup is frequently used for network troubleshooting, DNS diagnostics, or automated network management tasks. The impact extends beyond simple denial of service to include potential privilege escalation and system compromise scenarios.
Mitigation strategies for CVE-2002-1551 should prioritize immediate patching of affected IBM AIX systems with the vendor-provided security updates. Organizations should implement network segmentation and access controls to limit exposure of systems running nslookup commands, particularly in environments where the utility is used for network diagnostics. Network administrators should consider implementing DNS filtering mechanisms and monitoring for suspicious DNS traffic patterns that could indicate exploitation attempts. The vulnerability also highlights the importance of input validation and bounds checking in system utilities, aligning with ATT&CK technique T1059.007 for command and script interpreter execution. Additionally, organizations should establish secure coding practices for system utilities and implement regular security assessments to identify similar buffer overflow vulnerabilities in other network tools and applications. System hardening measures including disabling unnecessary network services and implementing least privilege access controls can further reduce the attack surface for exploitation of this vulnerability.