CVE-1999-1574 in AIX
Summary
by MITRE
Buffer overflow in the lex routines of nslookup for AIX 4.3 may allow attackers to cause a core dump and possibly execute arbitrary code via "long input strings."
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 11/12/2024
The vulnerability described in CVE-1999-1574 represents a classic buffer overflow flaw within the lex lexical analysis routines of the nslookup utility on AIX 4.3 systems. This issue resides in the fundamental input handling mechanisms that process domain name queries and other network lookup parameters. The flaw manifests when the application encounters input strings that exceed predetermined buffer limits, creating an exploitable condition that can lead to system instability and potential code execution. The vulnerability is particularly concerning because it affects a core network utility that is widely used for DNS resolution and system administration tasks.
The technical implementation of this buffer overflow stems from inadequate input validation within the lex parser components that nslookup employs to process command-line arguments and DNS query parameters. When users provide excessively long input strings, the lex routines fail to properly bounds-check the data before copying it into fixed-size memory buffers. This lack of proper input sanitization creates a condition where attacker-controlled data can overwrite adjacent memory locations, potentially corrupting program execution flow. The vulnerability specifically impacts AIX 4.3 systems where the lex library implementation does not adequately enforce buffer boundaries during string processing operations. According to CWE standards, this maps directly to CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which addresses out-of-bounds write vulnerabilities.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable remote code execution on affected systems. When the buffer overflow occurs, it can cause the nslookup process to crash and generate core dump files, disrupting network services and administrative operations. More critically, skilled attackers can potentially craft malicious input sequences that manipulate the program's execution flow to inject and execute arbitrary code with the privileges of the running nslookup process. This represents a significant security risk for systems where nslookup is accessible to untrusted users or when the utility is used in automated network management scenarios. The vulnerability affects the integrity and availability of network infrastructure services that depend on proper DNS resolution capabilities.
Mitigation strategies for CVE-1999-1574 should focus on immediate patching of affected AIX systems through official IBM security updates that address the buffer overflow conditions in the lex routines. System administrators should implement input length restrictions and validation mechanisms to prevent excessively long strings from reaching the vulnerable parsing routines. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, ensuring that even if an attacker successfully exploits the vulnerability, they cannot easily escalate privileges or access critical system resources. Additionally, monitoring systems should be configured to detect unusual nslookup activity patterns that might indicate exploitation attempts. Organizations should also consider implementing network access controls to limit who can execute nslookup commands and when, reducing the attack surface for this particular vulnerability. The remediation process should include thorough testing of patched systems to ensure that the buffer overflow conditions are properly resolved without introducing new compatibility issues in network management workflows.