CVE-2002-1109 in Virus Scanner
Summary
by MITRE
securetar, as used in AMaViS shell script 0.2.1 and earlier, allows users to cause a denial of service (CPU consumption) via a malformed TAR file, possibly via an incorrect file size parameter.
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Analysis
by VulDB Data Team • 04/19/2019
The vulnerability identified as CVE-2002-1109 affects the securetar component within AMaViS shell script version 0.2.1 and earlier. This issue represents a classic denial of service weakness that can be exploited through manipulation of TAR archive structures. The vulnerability specifically targets the file size parameter handling within the securetar utility, which is designed to process and validate email attachments within the AMaViS email filtering system. When a maliciously crafted TAR file is processed, the utility fails to properly handle incorrect file size parameters, leading to excessive CPU consumption during the parsing process.
The technical flaw stems from inadequate input validation and error handling within the securetar implementation. When processing a malformed TAR archive containing incorrect file size parameters, the utility enters into a resource-intensive loop or recursive processing pattern that consumes excessive CPU cycles. This behavior is consistent with CWE-400, which catalogs "Uncontrolled Resource Consumption" as a vulnerability category that encompasses denial of service conditions caused by improper handling of resource parameters. The flaw operates at the parsing layer of the TAR file format, where the utility attempts to validate file sizes and extract content without proper bounds checking or parameter validation.
From an operational impact perspective, this vulnerability creates a significant security concern for email servers and filtering systems that rely on AMaViS for content inspection. An attacker can exploit this weakness by sending a specially crafted email containing a malformed TAR attachment, causing the target system to consume excessive CPU resources and potentially leading to service disruption. The attack is particularly concerning because it requires minimal privileges and can be executed through standard email communication channels. This makes it a viable vector for DoS attacks against email infrastructure, potentially affecting organizations that process large volumes of email traffic. The vulnerability aligns with ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" through resource exhaustion attacks.
The mitigation strategies for this vulnerability include immediate upgrading to AMaViS versions that contain fixed securetar implementations, applying patches that correct the file size parameter validation logic, and implementing additional email filtering rules that can detect and quarantine suspicious TAR attachments. Organizations should also consider implementing rate limiting and resource monitoring to detect unusual CPU consumption patterns that may indicate exploitation attempts. Additionally, network administrators should ensure that email servers maintain adequate resource allocation and implement proper logging mechanisms to track potential exploitation attempts. The fix typically involves implementing proper bounds checking for file size parameters and adding robust error handling to prevent the utility from entering resource-intensive processing loops when encountering malformed input data.