CVE-2000-0609 in DMailWeb
Summary
by MITRE
NetWin dMailWeb and cwMail 2.6g and earlier allows remote attackers to cause a denial of service via a long username parameter.
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Analysis
by VulDB Data Team • 04/05/2019
The vulnerability identified as CVE-2000-0609 affects NetWin dMailWeb and cwMail versions 2.6g and earlier, representing a classic denial of service flaw that exploits improper input validation mechanisms within the mail server software. This vulnerability specifically targets the username parameter handling functionality, where the application fails to adequately validate or limit the length of user input during authentication processes. The flaw exists in the server-side processing logic that does not implement proper bounds checking or input sanitization for authentication parameters, creating an exploitable condition that can be leveraged by remote attackers to disrupt service availability.
The technical implementation of this vulnerability stems from the application's failure to enforce reasonable length constraints on username inputs, allowing malicious actors to submit excessively long parameter values that can cause memory allocation issues or buffer overflows within the server's processing stack. When the system attempts to process these malformed inputs, it can trigger memory corruption conditions or consume excessive system resources, leading to application instability and service disruption. This type of vulnerability aligns with CWE-122, which describes buffer overflow conditions that occur when a program writes data beyond the boundaries of a fixed-length buffer, and also relates to CWE-400, which covers resource exhaustion vulnerabilities that can lead to denial of service conditions. The attack vector is particularly concerning as it requires no authentication to exploit and can be executed remotely, making it a significant threat to system availability.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by attackers to systematically degrade system performance or completely terminate service availability for legitimate users. In environments where email services are critical for business operations, this vulnerability can result in substantial downtime and productivity losses. The vulnerability also represents a potential stepping stone for more sophisticated attacks, as initial denial of service conditions can be used to mask other malicious activities or create opportunities for privilege escalation attempts. From an attacker's perspective, this vulnerability fits within the ATT&CK framework under the T1499 category of network denial of service, specifically targeting the T1499.004 sub-technique related to network resource exhaustion attacks. Organizations using affected versions of NetWin dMailWeb and cwMail should consider this vulnerability as a high-priority threat that requires immediate remediation.
Mitigation strategies for CVE-2000-0609 should focus on implementing proper input validation controls that enforce reasonable length limits on authentication parameters, particularly username fields. System administrators should upgrade to patched versions of the affected software, as vendor releases typically include fixes that implement proper bounds checking and input sanitization mechanisms. Network-level protections such as rate limiting and connection throttling can provide additional defense-in-depth measures to limit the impact of exploitation attempts. The implementation of proper error handling and graceful degradation mechanisms within the application can also help prevent complete service termination when malformed inputs are encountered. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious parameter lengths being submitted to authentication endpoints, providing early warning capabilities for potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar input validation flaws in other legacy systems that may be susceptible to similar attack patterns.