CVE-2021-25035 in WP Time Capsule Plugin
Summary
by MITRE • 01/24/2022
The Backup and Staging by WP Time Capsule WordPress plugin before 1.22.7 does not sanitise and escape the error parameter before outputting it back in an admin page, leading to a Reflected Cross-Site Scripting
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Analysis
by VulDB Data Team • 01/27/2022
The vulnerability identified as CVE-2021-25035 affects the Backup and Staging by WP Time Capsule WordPress plugin version 1.22.7 and earlier, representing a critical security flaw that exposes administrators to reflected cross-site scripting attacks. This vulnerability resides within the plugin's handling of user-supplied input in the error parameter, which is processed without proper sanitization or escaping mechanisms before being rendered in administrative contexts. The flaw specifically impacts the plugin's administrative interface where error messages are displayed to users, creating an attack vector that can be exploited by malicious actors to inject malicious scripts into the browser of authenticated administrators.
The technical implementation of this vulnerability stems from improper input validation and output escaping practices within the plugin's codebase. When the plugin encounters an error condition during backup or staging operations, it typically displays error messages to the administrator interface. However, the error parameter received from user input is not adequately sanitized or escaped before being embedded into the HTML output. This failure in input sanitization creates a direct pathway for attackers to inject malicious JavaScript code through crafted error messages that are then reflected back to the administrator's browser. The vulnerability aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws, and represents a classic case of reflected XSS where malicious input is immediately reflected in the application's response.
The operational impact of this vulnerability is significant as it allows attackers to execute arbitrary JavaScript code within the context of an authenticated administrator's browser session. This privilege escalation capability enables attackers to perform actions with the same permissions as the administrator, potentially leading to complete compromise of the WordPress installation. Attackers could leverage this vulnerability to steal session cookies, modify plugin settings, access sensitive data, or even install malicious code. The reflected nature of the vulnerability means that attackers can deliver attacks through phishing emails or malicious links that, when clicked by an administrator, would execute the malicious script in their browser. This makes the vulnerability particularly dangerous in environments where administrators frequently interact with external links or receive emails containing potentially malicious content.
Security mitigations for this vulnerability primarily involve updating to the patched version 1.22.7 or later, which implements proper input sanitization and output escaping mechanisms for the error parameter. Organizations should immediately prioritize patching this vulnerability as it requires no user interaction beyond visiting a malicious link, making it particularly effective for automated attacks. Additionally, implementing proper input validation at multiple layers, including the use of Content Security Policy headers, can provide additional defense-in-depth measures. The vulnerability demonstrates the critical importance of proper input sanitization and output escaping practices in web applications, particularly within administrative interfaces where elevated privileges exist. This case study reinforces the necessity of following secure coding practices and adhering to the principles outlined in the OWASP Top Ten and NIST Cybersecurity Framework, specifically addressing the need for robust input validation and output encoding to prevent XSS vulnerabilities that can lead to complete system compromise.