CVE-2015-2020 in MyScript
Summary
by MITRE
The MyScript SDK before 1.3 for Android might allow attackers to execute arbitrary code by leveraging a finalize method in a Serializable class that improperly passes an attacker-controlled pointer to a native function.
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Analysis
by VulDB Data Team • 01/18/2020
The vulnerability identified as CVE-2015-2020 resides within the MyScript SDK version 1.2 and earlier for Android platforms, representing a critical security flaw that enables remote code execution through improper handling of serialized objects. This vulnerability specifically targets the Android serialization mechanism and exploits a dangerous pattern in how the SDK manages object deserialization processes. The flaw manifests in a finalize method within a Serializable class that inadvertently accepts an attacker-controlled pointer and forwards it to native code functions, creating a pathway for arbitrary code execution.
The technical exploitation of this vulnerability follows a well-documented pattern that aligns with CWE-502, which describes "Deserialization of Untrusted Data" as a fundamental weakness in software security. Attackers can craft malicious serialized objects that, when processed by the vulnerable MyScript SDK, trigger the problematic finalize method. This method receives attacker-controlled data that gets interpreted as a function pointer or memory address, allowing the attacker to redirect execution flow to arbitrary native code. The vulnerability's severity is amplified by the fact that it operates at the boundary between managed Java code and native Android components, where the security boundaries are often less strictly enforced.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise. When exploited, the vulnerability allows attackers to execute arbitrary commands with the privileges of the affected application, potentially leading to data theft, persistent backdoor installation, or further escalation attacks. The attack surface is particularly concerning because the MyScript SDK is commonly integrated into applications that handle sensitive user data, making the exploitation potentially widespread. The vulnerability affects not only the immediate application but also any system components that rely on the SDK's functionality, creating cascading security implications.
Security professionals should implement multiple layers of defense to mitigate this vulnerability. The primary mitigation involves upgrading to MyScript SDK version 1.3 or later, which includes proper serialization handling and eliminates the dangerous finalize method pattern. Additionally, developers should avoid implementing custom finalize methods in serializable classes and instead use safer serialization alternatives such as Parcelable interfaces. Network-level defenses can include monitoring for unusual deserialization patterns and implementing application whitelisting to restrict which applications can interact with vulnerable SDK components. Organizations should also consider implementing runtime application self-protection measures that can detect and prevent exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1059.007 for "Command and Scripting Interpreter: Python" and T1068 for "Exploitation for Privilege Escalation" when considering the potential for privilege escalation through native code execution.