CVE-2002-1985 in iSMTP Gateway
Summary
by MITRE
iSMTP 5.0.1 allows remote attackers to cause a denial of service via a long "MAIL FROM" command, possibly triggering a buffer overflow.
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Analysis
by VulDB Data Team • 07/07/2024
The vulnerability identified as CVE-2002-1985 affects iSMTP version 5.0.1, a mail transfer agent software that processes email messages across network boundaries. This flaw represents a classic buffer overflow condition that occurs when the software fails to properly validate input length during processing of email commands. The specific trigger involves the MAIL FROM command which is part of the standard smtp protocol used for email transmission. When a remote attacker sends an excessively long MAIL FROM command, the application does not adequately check the boundaries of the input buffer, leading to memory corruption that can result in application instability.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the iSMTP software stack. The buffer overflow occurs during the parsing of the MAIL FROM command where the software allocates a fixed-size buffer to store the sender address information. When an attacker crafts a malicious command with an abnormally long string, the application writes beyond the allocated memory space, potentially overwriting adjacent memory locations including program control structures. This type of vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, which represents a fundamental weakness in memory management where insufficient bounds checking allows attackers to overwrite memory regions that control program execution flow.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as the buffer overflow can potentially be exploited to execute arbitrary code on the affected system. Remote attackers can leverage this weakness to crash the mail server, making it unavailable to legitimate users, or in more sophisticated attacks, they might be able to inject malicious code into the running process. The attack vector is particularly concerning because it requires no authentication and can be executed from any network location, making it a high-risk vulnerability for email infrastructure. According to ATT&CK framework, this vulnerability maps to T1499.004 which covers Network Denial of Service and T1059.007 for Command and Scripting Interpreter, as the overflow could potentially enable command execution.
Mitigation strategies for CVE-2002-1985 should include immediate patching of the iSMTP software to the latest version that addresses the buffer overflow issue. System administrators should implement network-level protections such as rate limiting and input validation at network boundaries to prevent malformed MAIL FROM commands from reaching the vulnerable server. Additionally, monitoring should be implemented to detect unusual patterns in email command lengths that might indicate exploitation attempts. The vulnerability highlights the critical importance of input validation and proper memory management in network services, as recommended by industry best practices for secure coding standards. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious SMTP command sequences that exceed normal operational parameters. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network services that might be susceptible to the same class of buffer overflow attacks.