CVE-2016-2036 in Note 3
Summary
by MITRE
The getURL function in drivers/secfilter/urlparser.c in secfilter in the Samsung kernel for Android on SM-N9005 build N9005XXUGBOB6 (Note 3) and SM-G920F build G920FXXU2COH2 (Galaxy S6) devices allows attackers to trigger a NULL pointer dereference via a "GET HTTP/1.1" request, aka SVE-2016-5036.
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Analysis
by VulDB Data Team • 08/30/2020
The vulnerability identified as CVE-2016-2036 represents a critical NULL pointer dereference flaw within the Samsung kernel's security filtering component, specifically affecting Android devices running kernel versions that incorporate the secfilter driver. This issue manifests in the getURL function located in drivers/secfilter/urlparser.c, which processes HTTP requests within the kernel space of Samsung's mobile devices. The vulnerability affects Samsung Galaxy Note 3 (SM-N9005) and Galaxy S6 (SM-G920F) models, with specific build versions N9005XXUGBOB6 and G920FXXU2COH2 respectively, making it a device-specific kernel-level exploit vector.
The technical exploitation of this vulnerability occurs when an attacker crafts a specially malformed "GET HTTP/1.1" request that triggers the getURL function in the secfilter driver. The flaw stems from inadequate input validation and null pointer checks within the URL parsing logic, where the function fails to properly validate pointers before dereferencing them. This allows an attacker to manipulate the kernel execution flow by sending a malicious HTTP request that causes the kernel to attempt to access a null pointer, resulting in a kernel panic or system crash. The vulnerability is categorized under CWE-476 as a NULL Pointer Dereference, which is a common class of software defects that can lead to system instability and potential privilege escalation.
The operational impact of this vulnerability extends beyond simple system crashes, as it represents a potential attack vector that could be leveraged for more sophisticated exploits. When the kernel encounters the NULL pointer dereference, the system becomes unstable and may crash completely, leading to denial of service conditions that could be exploited in a persistent manner. The secfilter driver is designed to provide network security filtering capabilities, making this vulnerability particularly concerning as it could potentially allow attackers to bypass security measures or escalate privileges within the kernel space. This type of vulnerability aligns with ATT&CK technique T1068 which involves exploiting legitimate credentials or privileges to gain access to systems, though in this case the exploitation occurs at the kernel level rather than through credential compromise.
The mitigation strategies for CVE-2016-2036 primarily involve updating the affected Samsung devices to patched kernel versions that include proper null pointer validation in the getURL function. Samsung released security updates addressing this specific vulnerability, and users should ensure their devices are running the latest kernel versions. Additionally, network administrators and security professionals should monitor for any attempts to exploit this vulnerability in mobile device environments, particularly in corporate settings where Samsung devices may be used. The vulnerability highlights the importance of kernel-level input validation and proper error handling in security-critical components, as it demonstrates how a simple oversight in pointer validation can lead to system-wide stability issues. Organizations should also consider implementing network-based intrusion detection systems that can identify and block malicious HTTP requests that attempt to trigger this specific kernel vulnerability.