CVE-2021-40180 in App
Summary
by MITRE • 07/27/2022
In the WeChat application 8.0.10 for Android and iOS, a mini program can obtain sensitive information from a user's address book via wx.searchContacts.
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Analysis
by VulDB Data Team • 07/27/2022
The vulnerability identified as CVE-2021-40180 represents a significant privacy and security flaw within the WeChat messaging application across mobile platforms. This issue affects versions 8.0.10 for both Android and iOS operating systems, where a malicious mini program can exploit an exposed API function to access user contact information without proper authorization. The vulnerability specifically leverages the wx.searchContacts functionality which should normally be restricted to prevent unauthorized access to personal address book data.
The technical implementation of this vulnerability stems from inadequate access controls and permission validation within the WeChat mini program runtime environment. When a mini program invokes the wx.searchContacts API, the application fails to properly verify whether the calling program has legitimate authorization to access the user's contact list. This represents a clear violation of the principle of least privilege and demonstrates a failure in the application's security model. The flaw allows any mini program to potentially harvest sensitive personal information including phone numbers, email addresses, and contact names that users have stored in their address books.
From an operational perspective, this vulnerability creates substantial risk for WeChat users who may unknowingly interact with malicious mini programs that silently collect their contact information. The impact extends beyond simple privacy concerns as contact data can be used for social engineering attacks, phishing campaigns, or identity theft operations. Attackers could aggregate this information to build comprehensive profiles of users, potentially targeting them with more sophisticated and convincing attacks. The vulnerability is particularly concerning given WeChat's widespread adoption in regions where it serves as a primary communication platform, amplifying the potential attack surface and impact.
The security implications of CVE-2021-40180 align with CWE-284, which addresses improper access control mechanisms, and can be mapped to ATT&CK technique T1566 for social engineering through malicious applications. The vulnerability demonstrates how mobile application ecosystems can be exploited when proper sandboxing and permission controls are not enforced. Organizations and users should consider implementing additional security measures such as regularly reviewing application permissions, avoiding interaction with untrusted mini programs, and maintaining updated versions of mobile applications. The incident highlights the critical importance of robust API security testing and proper access control implementation in mobile application development, particularly for platforms that handle sensitive personal data. Users should be cautious about granting permissions to mini programs and should regularly audit their installed applications and their associated data access permissions.