CVE-2019-10251 in UC Browser
Summary
by MITRE
The UCWeb UC Browser application through 2019-03-26 for Android uses HTTP to download certain modules associated with PDF and Microsoft Office files (related to libpicsel), which allows MITM attacks.
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Analysis
by VulDB Data Team • 08/17/2023
The vulnerability identified as CVE-2019-10251 affects the UCWeb UC Browser application version 12.12.0 and earlier for Android devices, representing a significant security weakness in the application's network communication protocols. This flaw stems from the browser's implementation of insecure communication practices when handling specific file types, particularly those related to PDF and Microsoft Office documents. The application's reliance on unencrypted HTTP connections for downloading modules associated with these file formats creates a persistent attack surface that adversaries can exploit to compromise user data and system integrity.
The technical implementation of this vulnerability manifests through the browser's use of HTTP instead of HTTPS for downloading components from the libpicsel library, which is responsible for processing and rendering various document types. This design decision exposes the application to man-in-the-middle attacks where malicious actors positioned between the user and the download server can intercept, modify, or inject malicious code into the downloaded modules. The vulnerability specifically impacts the download process of PDF and Microsoft Office file handling components, making it particularly dangerous for users who frequently access or process such documents within the browser environment. The flaw represents a direct violation of secure communication best practices and demonstrates poor implementation of network security controls.
The operational impact of this vulnerability extends beyond simple data interception, as it enables adversaries to potentially modify the downloaded modules to include malicious functionality that could compromise the entire device. Attackers could leverage this weakness to inject backdoors, trojans, or other malware into the browser's document processing capabilities, creating persistent threats that could compromise user privacy and system security. The vulnerability affects users who regularly access document files through the browser, making it particularly concerning for enterprise environments where sensitive business documents are frequently handled. This weakness also undermines user trust in the application's security model and could lead to broader reputational damage for the vendor.
Security professionals should consider this vulnerability in the context of the CWE-319 category, which specifically addresses the exposure of sensitive information via network transmission, and aligns with ATT&CK technique T1041 for Exfiltration Over C2 Channel. The vulnerability demonstrates a failure in implementing proper transport layer security measures and represents a common weakness found in mobile applications that prioritize user experience over security. Organizations should immediately implement mitigations including mandatory HTTPS enforcement for all downloads, network monitoring for suspicious traffic patterns, and user education regarding the risks of accessing untrusted documents through insecure applications. The vendor should prioritize releasing a patched version that enforces HTTPS connections for all module downloads while implementing proper certificate validation mechanisms to prevent similar vulnerabilities in future releases.