CVE-2020-28702 in PybbsCMS
Summary
by MITRE • 11/01/2021
A SQL injection vulnerability in TopicMapper.xml of PybbsCMS v5.2.1 allows attackers to access sensitive database information.
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Analysis
by VulDB Data Team • 11/04/2021
The vulnerability identified as CVE-2020-28702 represents a critical SQL injection flaw within PybbsCMS version 5.2.1 that specifically targets the TopicMapper.xml component. This weakness arises from inadequate input validation and sanitization mechanisms within the application's database interaction layer, creating an exploitable entry point for malicious actors to manipulate database queries through crafted user inputs. The vulnerability exists in the application's data access object pattern implementation where user-supplied parameters are directly incorporated into SQL statements without proper escaping or parameterization, violating fundamental security principles of input validation and query isolation.
The technical exploitation of this vulnerability occurs when an attacker manipulates input fields that are processed by the TopicMapper.xml file, which serves as the data mapping layer for topic-related database operations. This allows attackers to inject malicious SQL code that bypasses normal authentication mechanisms and directly interacts with the underlying database system. The flaw specifically manifests when the application fails to properly sanitize or escape user-provided data before incorporating it into database queries, enabling attackers to execute arbitrary SQL commands with the privileges of the database user account. This type of vulnerability is classified under CWE-89 as SQL Injection, which is a well-documented weakness in web application security that has been consistently ranked among the top ten web application security risks by OWASP.
The operational impact of this vulnerability extends beyond simple data theft, as it can enable complete database compromise and potential system takeover. Attackers can leverage this weakness to extract sensitive user credentials, personal information, forum content, and other confidential data stored within the CMS database. The vulnerability may also facilitate privilege escalation attacks where attackers can elevate their access levels to gain administrative control over the entire forum system. Additionally, the compromised system could serve as a foothold for further lateral movement within network environments, particularly if the database server hosts other sensitive applications or services. According to ATT&CK framework, this vulnerability maps to T1071.005 for Application Layer Protocol: Web Protocols and T1046 for Network Service Scanning, as attackers would need to identify and exploit the specific endpoint to achieve their objectives.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements. The primary fix involves implementing proper parameterized queries or prepared statements throughout the TopicMapper.xml component and all related database access points, ensuring that user inputs are never directly concatenated into SQL commands. Input validation should be strengthened at multiple layers including client-side, server-side, and database-level to prevent malicious payloads from reaching the execution engine. The application should also implement proper output encoding and escaping mechanisms to prevent any potential cross-site scripting attacks that might occur if attackers manage to extract data through this vulnerability. Security monitoring and logging should be enhanced to detect unusual database access patterns and potential exploitation attempts. Organizations should also consider implementing web application firewalls, database activity monitoring tools, and regular security code reviews to identify similar vulnerabilities in other components. The remediation process should include thorough regression testing to ensure that the security fixes do not introduce functional regressions while maintaining the application's core functionality.