CVE-2001-0653 in Sendmail
Summary
by MITRE
Sendmail 8.10.0 through 8.11.5, and 8.12.0 beta, allows local users to modify process memory and possibly gain privileges via a large value in the category part of debugger (-d) command line arguments, which is interpreted as a negative number.
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Analysis
by VulDB Data Team • 10/05/2025
The vulnerability described in CVE-2001-0653 affects sendmail versions 8.10.0 through 8.11.5 and the 8.12.0 beta release, representing a critical memory corruption issue that can be exploited by local attackers to potentially escalate privileges. This flaw exists in the debugger command line argument processing mechanism where the category part of the -d flag is mishandled, leading to improper interpretation of user-supplied values as negative numbers. The vulnerability specifically targets the memory management routines within sendmail's debugging functionality, creating a scenario where crafted input can manipulate process memory structures.
The technical root cause of this vulnerability lies in the improper validation and interpretation of debugger category values passed through command line arguments. When users provide large numeric values to the category portion of the -d debugger command, the system fails to properly handle the conversion of these values into signed integers. This misinterpretation causes the system to treat large positive values as negative numbers, which can then be used to manipulate memory addresses and potentially overwrite critical process memory regions. The vulnerability manifests as a classic integer overflow or signedness error, where the boundary conditions for numeric input processing are not properly enforced.
From an operational perspective, this vulnerability presents a significant risk to systems running vulnerable sendmail versions, particularly in multi-user environments where local users might attempt to exploit the flaw. The local privilege escalation aspect means that attackers who already have access to the system can potentially elevate their privileges to gain higher-level system access. The impact extends beyond simple memory corruption, as the ability to manipulate process memory can lead to arbitrary code execution, making this a particularly dangerous vulnerability for system administrators to address. The vulnerability affects the core functionality of sendmail's debugging features, which are typically disabled in production environments but may be enabled during troubleshooting or development phases.
The mitigation strategies for this vulnerability should focus on immediate version updates to sendmail 8.11.6 or later, which contain the necessary patches to address the memory handling issue in debugger argument processing. System administrators should also implement strict access controls to limit local user privileges and disable debugging features in production environments where possible. Additionally, input validation measures should be enhanced to properly validate and sanitize numeric inputs to command line arguments, particularly those that are interpreted as memory addresses or control parameters. This vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and represents a classic example of how improper input validation can lead to memory corruption issues. The attack pattern described in the MITRE ATT&CK framework would fall under privilege escalation techniques, specifically leveraging local system vulnerabilities to gain elevated access rights. Organizations should conduct thorough vulnerability assessments to identify systems running vulnerable sendmail versions and implement comprehensive patch management procedures to address this and similar memory corruption vulnerabilities.