CVE-2017-7251 in pi-engine
Summary
by MITRE
A Cross-Site Scripting (XSS) was discovered in pi-engine/pi 2.5.0. The vulnerability exists due to insufficient filtration of user-supplied data (preview) passed to the "pi-develop/www/script/editor/markitup/preview/markdown.php" URL. An attacker could execute arbitrary HTML and script code in a browser in the context of the vulnerable website.
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Analysis
by VulDB Data Team • 11/15/2022
The vulnerability identified as CVE-2017-7251 represents a critical cross-site scripting flaw within the pi-engine/pi content management system version 2.5.0. This security weakness manifests in the application's handling of user-supplied input data, specifically within the preview functionality of the markitup editor component. The affected file path demonstrates a clear breakdown in input validation processes where data submitted through the preview mechanism fails to undergo proper sanitization before being rendered back to users. The vulnerability exists in the pi-develop/www/script/editor/markitup/preview/markdown.php endpoint, which processes user input without adequate filtering mechanisms to prevent malicious script execution.
The technical exploitation of this vulnerability occurs through the insufficient filtration of user-supplied data that flows through the preview functionality. When users submit content through the markitup editor, the system processes this input through the vulnerable markdown.php script without implementing proper output encoding or input validation measures. This allows attackers to inject malicious HTML and JavaScript code directly into the preview functionality, which then executes within the browser context of legitimate users. The vulnerability operates under the CWE-79 classification as a classic cross-site scripting flaw, where the application fails to properly validate or encode user-provided data before incorporating it into dynamically generated web pages. This weakness creates a direct pathway for attackers to establish persistent malicious sessions within the context of the vulnerable website.
The operational impact of this vulnerability extends beyond simple script execution capabilities, as it enables attackers to perform a wide range of malicious activities within the compromised environment. Successful exploitation allows threat actors to steal session cookies, redirect users to malicious websites, deface the website content, or even execute more sophisticated attacks such as credential theft or privilege escalation within the application's context. The vulnerability's presence in a content management system's editor component makes it particularly dangerous as it can be leveraged by attackers to compromise not just individual user sessions but potentially the entire application infrastructure. The attack surface is further expanded due to the preview functionality being accessible to authenticated users, potentially allowing for more targeted and effective exploitation strategies.
Mitigation strategies for CVE-2017-7251 should focus on implementing comprehensive input validation and output encoding measures throughout the affected application components. The primary remediation involves ensuring that all user-supplied data passing through the markdown.php endpoint undergoes strict sanitization processes before any rendering occurs. This includes implementing proper HTML escaping mechanisms, validating input against whitelisted character sets, and employing Content Security Policy headers to prevent unauthorized script execution. Organizations should also consider implementing regular security assessments and input validation reviews to identify similar vulnerabilities in other application components. The remediation process aligns with ATT&CK technique T1203 which focuses on exploiting web application vulnerabilities, making proper input validation and output encoding critical defensive measures. Additionally, the vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing robust security development practices to prevent such flaws from entering production environments.