CVE-2019-6740 in Galaxy S9
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Samsung Galaxy S9 prior to January 2019 Security Update (SMR-JAN-2019 - SVE-2018-13467). User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the ASN.1 parser. When parsing ASN.1 strings, the process does not properly validate the length of user-supplied data prior to copying it to a fixed-length heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-7472.
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Analysis
by VulDB Data Team • 09/26/2023
The vulnerability identified as CVE-2019-6740 represents a critical buffer overflow flaw within the Samsung Galaxy S9's ASN.1 parser implementation, affecting devices prior to the January 2019 security update. This vulnerability operates under the CWE-121 CWE category, specifically addressing buffer overflow conditions where insufficient validation of input data length leads to memory corruption. The flaw exists in the handling of ASN.1 (Abstract Syntax Notation One) encoded data structures, which are commonly used in telecommunications and security protocols for encoding data structures. The vulnerability manifests when the system processes ASN.1 strings without proper bounds checking before copying data into a fixed-size heap-based buffer, creating a condition where attacker-controlled data can overwrite adjacent memory locations.
The exploitation of this vulnerability requires user interaction, making it a client-side attack vector that typically involves social engineering tactics to lure victims into visiting malicious websites or opening harmful attachments. According to the ATT&CK framework, this vulnerability maps to T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute malicious code on target systems. The attack surface is particularly concerning given that the Galaxy S9 was a widely deployed smartphone model, with millions of devices potentially affected by this flaw. The vulnerability's impact extends beyond simple code execution to potentially allow full system compromise, as the attacker can execute code within the context of the current process, which may have elevated privileges depending on the application's security model.
The technical implementation of this vulnerability demonstrates poor input validation practices where the ASN.1 parser fails to verify that user-supplied data lengths do not exceed the allocated buffer capacity. When the parsing routine encounters ASN.1 encoded strings, it performs a direct copy operation without validating whether the source data length exceeds the destination buffer size, which is a classic buffer overflow condition. This allows attackers to craft malicious ASN.1 structures that, when processed by the vulnerable system, result in memory corruption and arbitrary code execution. The heap-based buffer nature of the vulnerability means that the memory corruption can potentially affect other heap-managed objects, leading to more complex exploitation scenarios including information disclosure or denial of service conditions. The vulnerability's classification as a remote code execution flaw underscores its severity, as it does not require physical access to the device or local network privileges to exploit.
The operational impact of CVE-2019-6740 extends beyond individual device compromise to potentially affect enterprise environments where Samsung Galaxy S9 devices are used for business operations. Organizations relying on these devices for corporate communications or security-sensitive applications face significant risks, as successful exploitation could lead to data breaches, unauthorized access to corporate networks, or complete device takeover. The vulnerability's presence in the ASN.1 parser component makes it particularly dangerous because ASN.1 is widely used in various security protocols including SSL/TLS certificates, LDAP, and various telecommunications standards, meaning that a single malicious certificate or data structure could trigger exploitation. Security researchers have noted that this vulnerability aligns with the broader category of parsing vulnerabilities that have historically been prime targets for attackers due to their ability to cause widespread impact with relatively simple exploitation techniques. The fact that this vulnerability was tracked as ZDI-CAN-7472 indicates it was recognized by the Zero Day Initiative as a significant security flaw requiring immediate attention and patching. Organizations should prioritize updating affected devices to the January 2019 security patch or implementing network-level mitigations to prevent exploitation attempts while awaiting full patch deployment.