CVE-2018-20726 in Cacti
Summary
by MITRE
A cross-site scripting (XSS) vulnerability exists in host.php (via tree.php) in Cacti before 1.2.0 due to lack of escaping of unintended characters in the Website Hostname field for Devices.
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Analysis
by VulDB Data Team • 07/01/2023
This cross-site scripting vulnerability in Cacti affects versions prior to 1.2.0 and specifically targets the host.php script which is accessed through tree.php. The flaw occurs when processing user input in the Website Hostname field for Devices, where the application fails to properly sanitize or escape potentially malicious content. This represents a classic XSS vulnerability where untrusted data flows directly into the application's output without adequate validation or encoding mechanisms. The vulnerability exists at the input sanitization layer, where the system does not adequately filter or escape special characters that could be interpreted as executable code by web browsers.
The technical implementation of this flaw allows attackers to inject malicious scripts into the Website Hostname field during device configuration. When other users view the device information or navigate through the tree.php interface, the malicious content gets executed in their browser context. This type of vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws in software applications. The attack vector is particularly dangerous because it can be exploited through legitimate administrative functions, making it difficult to detect and trace back to the original source. The vulnerability demonstrates poor input validation practices where the application assumes that user-supplied data will be benign, leading to potential code execution in victim browsers.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to perform session hijacking, steal sensitive information, redirect users to malicious sites, or perform actions on behalf of authenticated users. An attacker who can manipulate the Website Hostname field can potentially execute arbitrary JavaScript code in the context of other users' sessions, which aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter. This vulnerability is particularly concerning in network monitoring environments where Cacti is used, as it could allow attackers to gain unauthorized access to monitoring data or manipulate device configurations. The risk is amplified when considering that Cacti is often used in enterprise environments where it may be accessed by multiple administrators and users, creating a wide attack surface.
Mitigation strategies should focus on implementing proper input validation and output encoding mechanisms throughout the application. The most effective approach is to sanitize all user-supplied input before processing or displaying it, particularly in fields that may contain HTML or script content. This includes implementing proper HTML escaping for all output contexts and establishing strict input validation rules for the Website Hostname field. Organizations should upgrade to Cacti version 1.2.0 or later where this vulnerability has been addressed through improved input sanitization. Additional protective measures include implementing content security policies, restricting administrative privileges to trusted users only, and monitoring for suspicious activities in the device management sections of the application. The fix should also include proper error handling and logging to detect potential exploitation attempts and ensure that all user inputs are properly validated against expected formats and character sets.