CVE-2022-23391 in Pybbs
Summary
by MITRE • 02/15/2022
A cross-site scripting (XSS) vulnerability in Pybbs v6.0 allows attackers to execute arbitrary web scripts or HTML via a crafted payload inserted into the Search box.
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Analysis
by VulDB Data Team • 02/18/2022
The vulnerability identified as CVE-2022-23391 represents a critical cross-site scripting flaw within the Pybbs v6.0 bulletin board system that fundamentally compromises user session integrity and application security. This issue arises from insufficient input validation and output encoding mechanisms within the search functionality, creating an attack vector that enables malicious actors to inject and execute arbitrary web scripts or HTML content. The vulnerability specifically targets the Search box parameter, which serves as an entry point for attackers to manipulate the application's behavior and potentially escalate their privileges within the system.
The technical exploitation of this XSS vulnerability stems from the application's failure to properly sanitize user input before processing and displaying search results. When a user submits a search query containing malicious payload, the system does not adequately filter or encode special characters that could be interpreted as executable code by web browsers. This weakness allows attackers to craft payloads that, when executed, can steal session cookies, redirect users to malicious websites, or perform unauthorized actions on behalf of authenticated users. The vulnerability manifests as a classic reflected XSS attack where the malicious script is reflected back to the user through the search functionality, making it particularly dangerous for web applications that rely on user-generated content and search features.
From an operational impact perspective, this vulnerability creates significant risks for forum administrators and users alike. Attackers can leverage this flaw to hijack user sessions, potentially gaining unauthorized access to sensitive forums and personal information. The attack surface extends beyond simple script execution to include more sophisticated exploitation techniques such as credential theft, data exfiltration, and the potential for privilege escalation within the forum environment. The impact is particularly severe for communities that rely heavily on user interactions and maintain sensitive discussions, as the vulnerability could be exploited to compromise entire user bases and undermine trust in the platform's security measures.
Security mitigations for CVE-2022-23391 should prioritize immediate implementation of proper input validation and output encoding mechanisms within the search functionality. The recommended approach involves implementing strict sanitization of all user inputs, particularly those that are displayed in web responses, to prevent the execution of malicious scripts. This includes applying context-specific encoding techniques such as HTML entity encoding for output, implementing Content Security Policy headers to restrict script execution, and utilizing parameterized queries to prevent injection attacks. Organizations should also consider implementing web application firewalls to detect and block suspicious search queries, while ensuring that all users are running patched versions of the Pybbs software. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a clear violation of the principle of least privilege and secure input handling as outlined in various cybersecurity frameworks and standards including those referenced in the ATT&CK framework under the web application attack patterns.