CVE-2015-3837 in Android
Summary
by MITRE
The OpenSSLX509Certificate class in org/conscrypt/OpenSSLX509Certificate.java in Android before 5.1.1 LMY48I improperly includes certain context data during serialization and deserialization, which allows attackers to execute arbitrary code via an application that sends a crafted Intent, aka internal bug 21437603.
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Analysis
by VulDB Data Team • 02/03/2018
The vulnerability described in CVE-2015-3837 represents a critical security flaw within the Android operating system's implementation of OpenSSL certificate handling mechanisms. This issue specifically affects the OpenSSLX509Certificate class located in the org/conscrypt/OpenSSLX509Certificate.java file, which serves as a core component in Android's cryptographic operations and certificate management infrastructure. The vulnerability stems from improper handling of context data during the serialization and deserialization processes, creating a dangerous attack vector that can be exploited by malicious actors to gain unauthorized code execution privileges.
The technical flaw manifests in how the OpenSSLX509Certificate class manages serialized data structures when processing certificate information within Android applications. During the serialization process, the class fails to properly sanitize or validate context data that gets embedded within the certificate objects, allowing attackers to inject malicious payloads that persist through the deserialization phase. This creates a classic deserialization vulnerability where untrusted input can be manipulated to execute arbitrary code within the application's security context. The vulnerability specifically affects Android versions prior to 5.1.1 LMY48I, indicating that it was a widespread issue across multiple Android releases and affected a significant portion of mobile devices running these versions.
The operational impact of this vulnerability extends far beyond simple certificate handling, as it allows attackers to leverage crafted Intents to deliver malicious payloads through legitimate Android applications. When an application processes a specially crafted Intent containing manipulated certificate data, the vulnerable deserialization logic can be triggered, leading to arbitrary code execution with the privileges of the affected application. This represents a serious escalation of privilege attack vector that can be exploited in the context of a targeted application, potentially allowing attackers to access sensitive data, modify application behavior, or even compromise the entire device. The vulnerability demonstrates how cryptographic libraries, when improperly implemented, can create attack surfaces that extend far beyond their intended security boundaries.
This vulnerability aligns with CWE-502, which describes deserialization of untrusted data, and can be mapped to ATT&CK technique T1059.007 for command and scripting interpreter usage, as well as T1068 for exploit for privilege escalation. The attack chain typically involves an attacker sending a malicious Intent through a legitimate application that processes certificate data, exploiting the improper serialization handling to gain code execution privileges. Organizations and users affected by this vulnerability should implement immediate mitigations including updating to Android 5.1.1 or later versions, applying security patches, and reviewing application code to ensure proper input validation and sanitization of certificate data. Additionally, security monitoring should be enhanced to detect unusual Intent processing patterns and certificate manipulation activities that could indicate exploitation attempts.