CVE-2019-0622 in Skype for Android
Summary
by MITRE
An elevation of privilege vulnerability exists when Skype for Andriod fails to properly handle specific authentication requests, aka "Skype for Android Elevation of Privilege Vulnerability." This affects Skype 8.35.
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Analysis
by VulDB Data Team • 04/26/2020
The CVE-2019-0622 vulnerability represents a critical elevation of privilege flaw within Skype for Android versions up to 8.35, specifically manifesting in the application's improper handling of authentication requests. This vulnerability falls under the broader category of privilege escalation issues that can fundamentally compromise the security posture of mobile applications. The flaw stems from inadequate validation mechanisms within the authentication flow, allowing malicious actors to potentially bypass normal access controls and gain elevated system privileges. The vulnerability is particularly concerning given Skype's widespread usage and its integration with various communication protocols that may expose additional attack vectors.
The technical implementation of this vulnerability demonstrates a failure in the application's authentication request processing logic, where specific malformed or manipulated authentication tokens or requests are not properly validated before being accepted. This represents a classic case of insufficient input validation and authentication flow control, which aligns with CWE-284 - "Improper Access Control" and CWE-285 - "Improper Authorization." The flaw likely exists in how the application processes authentication responses or handles session management during the authentication lifecycle, potentially allowing attackers to inject malicious authentication data that bypasses standard security checks. Attackers could exploit this by crafting specific authentication requests that leverage the application's trust model in unintended ways, potentially gaining access to user data, system resources, or other unauthorized privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it could enable attackers to access sensitive user communications, personal information, and potentially establish persistent access to devices. Mobile applications like Skype often handle sensitive data including messages, contacts, call logs, and media files, making this vulnerability particularly dangerous. The exploitation of such a flaw could lead to full device compromise, data exfiltration, or the establishment of backdoors. From an attacker's perspective, this vulnerability would map to several ATT&CK techniques including T1068 - "Exploitation for Privilege Escalation" and T1566 - "Phishing", as the attack chain might involve social engineering to trigger the vulnerable authentication flow. The impact is further amplified by the fact that Skype is frequently used in enterprise environments where users may have access to sensitive corporate communications and data.
Mitigation strategies for CVE-2019-0622 should focus on immediate application updates and comprehensive security assessments of the authentication infrastructure. Organizations should ensure all Skype for Android installations are updated to versions that address this vulnerability, with particular attention to the authentication request handling mechanisms. Network monitoring should be enhanced to detect unusual authentication patterns or malformed requests that might indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and authentication flow design, emphasizing the need for thorough security testing of authentication mechanisms. Additionally, mobile device management solutions should be configured to enforce application updates and monitor for suspicious authentication behaviors, while security teams should implement proactive threat hunting to identify potential exploitation attempts within their networks. The remediation process must include comprehensive code review of authentication flows and implementation of proper access control mechanisms that align with industry best practices for mobile application security.