Description
A critical vulnerability has been identified in the login program on Aix (before version 4.0) that allows remote users to specify 100 or more environment variables when logging on. This exceeds the length of a specific string and possibly triggers a buffer overflow.
Affected Product(s)
- IBM AIX 3.2.5
Technical Details
The vulnerability, identified as CVE-2002-1689, is a critical flaw in the login program in IBM’s AIX operating system before version 4.0. The issue exists due to inadequate handling of environment variables. When a remote user specifies 100 or more environment variables during the login process, the total length of these variables can exceed the buffer’s capacity. This scenario potentially triggers a buffer overflow condition, leading to arbitrary code execution.
IBM AIX is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms. This OS has been widely adopted, particularly in enterprise environments, due to its stability and performance. AIX version 3.2.5 is particularly affected by this vulnerability. The improper management and restriction of memory operations characterize the weakness (CWE-119).
Buffer overflow vulnerabilities occur when more data is written to a buffer than it can hold. In this case, the overflow can overwrite adjacent memory, leading to unexpected behaviors such as corruption of data, crashes, or potential execution of malicious code. Buffer overflows have been a long-standing issue in software security, often leveraged by threat actors to exploit vulnerable systems.
The CVE-2002-1689 vulnerability is documented in various security databases, including the National Vulnerability Database (NVD) and Cisco Security Advisory pages. According to Cisco’s advisory, this vulnerability impacts the Solaris /bin/login program, considering it might be misattributed since IBM’s documentation confirms the issue relates to AIX systems.
The Equation Group, known for their sophisticated cyber-attacks and alleged links to the National Security Agency (NSA), have exploited similar vulnerabilities in the past. This group often targets high-value assets in critical infrastructures and enterprises, taking advantage of older, unpatched systems and rare vulnerabilities.
The immediate risk of this vulnerability is its potential to provide unauthorized users with root access or control over affected systems, which could have severe repercussions, including data breaches, system failures, and leveraged attacks on other connected systems. Given the high CVSSv2 rating of 10.0, the security community has classified this issue as high severity, urging administrators to patch or mitigate the exposure promptly.
Weakness
The weakness associated with this vulnerability is improper restriction of operations within the bounds of a memory buffer (CWE-119). This weakness arises because the software fails to properly manage the buffer length, allowing for excessive data inputs that exceed the bufferโs capacity and potentially resulting in arbitrary code execution or system crashes.
Impact Assessment
If exploited, this vulnerability could allow an attacker to gain unauthorized access to sensitive data or execute arbitrary code on the affected system. Moreover, the ability to specify an excessive number of environment variables during login could ultimately lead to complete system compromise, unauthorized administrative access, and severe operational disruptions.
Active Exploitation
We have observed activity from the adversary group Equation Group, which is known for targeting similar buffer overflow vulnerabilities in the past. This sophisticated group is notorious for leveraging uncommon exploits to infiltrate high-value targets, making it imperative for affected systems to apply necessary patches immediately.
Ransomware Association
The vulnerability has been linked to ransomware attacks, specifically incidents where attackers exploit buffer overflows to establish initial access. While detailed associations with specific ransomware strains are limited, the potential for this vulnerability to facilitate broader attack vectors, including ransomware deployment, remains significant.
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Mitigation and Resolution
We have released a patch that addresses this vulnerability. Administrators should update to version 4.0 or later of the AIX operating system immediately. This update rectifies the buffer overflow issue by implementing stricter limitations on environment variables during the login process, thus ensuring proper memory management within the affected component.
Recommendations
- We strongly recommend that all customers apply the latest patch as soon as possible.
- Update to IBM AIX version 4.0 or later to eliminate the vulnerability.
- Regularly check and apply updates or patches released by IBM for their AIX operating systems.
- Limit the capability of remote logins for administrative accounts to mitigate potential exposure.
- Implement network and host-based intrusion detection systems to identify and thwart attempts at exploitation.
- Perform a thorough review and audit of current environment variable handling procedures to ensure compliance with best practices and avoid similar vulnerabilities in the future.
Referencesย
- CISCO Security Advisory
- CVE MITRE Details
- NVD Database
- NeoHapsis Archives
- HPI Vulnerability Database
- XForce Vulnerability Advisory