CVE-2017-16230 in Typecho
Summary
by MITRE
In admin/write-post.php in Typecho through 1.1, one can log in to the background page, write a new article, and add payload in the article content, resulting in XSS via index.php/action/contents-post-edit.
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Analysis
by VulDB Data Team • 12/02/2019
The vulnerability identified as CVE-2017-16230 represents a cross-site scripting flaw in the Typecho content management system version 1.1 and earlier. This security issue exists within the administrative write-post.php component that handles article creation and editing functionality. The vulnerability allows authenticated attackers with administrative privileges to inject malicious scripts into blog posts through the content field, which are then executed when other users view the affected posts through the index.php/action/contents-post-edit endpoint.
The technical exploitation of this vulnerability relies on the improper sanitization of user input within the Typecho administrative interface. When administrators create or edit posts through the write-post.php script, the system fails to adequately validate or escape special characters in the article content field. This allows attackers to embed malicious javascript code or other harmful payloads that are stored in the database and subsequently executed in the context of other users' browsers when they access the affected posts. The vulnerability specifically manifests through the index.php/action/contents-post-edit endpoint which processes the saved content and displays it to users, creating a direct path for script execution.
The operational impact of this vulnerability extends beyond simple script injection as it provides attackers with the capability to perform various malicious activities including session hijacking, credential theft, redirection to malicious sites, and potential privilege escalation within the compromised Typecho installation. Since the vulnerability requires administrative access to exploit, it primarily affects organizations where attackers have gained administrative credentials or where privilege escalation occurs through other means. The attack vector is particularly concerning as it can remain undetected for extended periods, with malicious scripts executing silently in the background of compromised user sessions.
Organizations affected by this vulnerability should implement immediate mitigations including updating to Typecho version 1.1.1 or later where this vulnerability has been patched. The fix typically involves implementing proper input sanitization and output escaping mechanisms for all user-supplied content within the administrative interface. Additionally, administrators should review and enforce strict access controls to prevent unauthorized administrative access, implement web application firewalls to detect suspicious payloads, and conduct regular security audits of the CMS installation. This vulnerability aligns with CWE-79 which addresses cross-site scripting flaws, and could be categorized under ATT&CK technique T1059.007 for command and scripting interpreter usage in the context of malicious script execution within web applications.