CVE-2020-29600 in AWStats
Summary
by MITRE • 12/08/2020
In AWStats through 7.7, cgi-bin/awstats.pl?config= accepts an absolute pathname, even though it was intended to only read a file in the /etc/awstats/awstats.conf format. NOTE: this issue exists because of an incomplete fix for CVE-2017-1000501.
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Analysis
by VulDB Data Team • 12/13/2020
The vulnerability described in CVE-2020-29600 represents a critical path traversal flaw in the AWStats web analytics tool version 7.7 and earlier. This issue manifests in the cgi-bin/awstats.pl script where the configuration parameter accepts absolute pathnames instead of restricting input to files within the designated /etc/awstats/awstats.conf directory structure. The flaw stems from an incomplete remediation of a previous vulnerability CVE-2017-1000501, which demonstrates how security fixes can sometimes introduce new attack vectors when not thoroughly validated. The root cause aligns with CWE-22, which specifically addresses path traversal vulnerabilities where applications fail to properly validate or sanitize user-supplied input containing file path information.
The technical implementation of this vulnerability allows an attacker to manipulate the config parameter in the awstats.pl script to specify arbitrary absolute file paths on the server filesystem. This bypasses the intended security model that restricts configuration file access to the designated awstats configuration directory. When an attacker supplies a malicious absolute path, the application processes the file as if it were a legitimate configuration file, potentially exposing sensitive system information or enabling further exploitation. The flaw operates at the input validation layer where proper sanitization of user input should have prevented absolute path resolution, but instead the application accepts and processes these paths without adequate restrictions.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential access to critical system files that may contain sensitive configuration data, database credentials, or other system artifacts. An attacker could leverage this vulnerability to read arbitrary files on the server, potentially leading to privilege escalation or data exfiltration. The vulnerability affects systems where AWStats is installed and accessible via web interface, making it particularly dangerous in environments where web applications have broad filesystem access. This issue particularly impacts organizations using AWStats for web log analysis who may not have properly configured their web server security measures to restrict access to sensitive files.
Mitigation strategies should focus on implementing proper input validation and sanitization of the config parameter to ensure only relative paths within the designated configuration directory are accepted. Organizations should immediately upgrade to AWStats version 7.8 or later where this vulnerability has been properly addressed. Network segmentation and web application firewall rules can provide additional protection by blocking direct access to the awstats.pl script or restricting the parameters that can be passed to it. The implementation should follow ATT&CK technique T1213.002 for credential access and T1083 for file and directory discovery, as attackers would typically attempt to enumerate system files after gaining initial access through this vulnerability. System administrators should also implement proper file permissions and access controls to limit what files the web application can read, reducing the potential impact of such vulnerabilities.