CVE-2016-7910 in Android
Summary
by MITRE • 01/25/2023
Use-after-free vulnerability in the disk_seqf_stop function in block/genhd.c in the Linux kernel before 4.7.1 allows local users to gain privileges by leveraging the execution of a certain stop operation even if the corresponding start operation had failed.
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Analysis
by VulDB Data Team • 01/25/2023
The CVE-2016-7910 vulnerability represents a critical use-after-free flaw in the Linux kernel's block device subsystem that enables local privilege escalation. This vulnerability exists within the disk_seqf_stop function located in block/genhd.c, affecting Linux kernel versions prior to 4.7.1. The flaw manifests when a specific stop operation executes despite a failed corresponding start operation, creating a scenario where freed memory objects are accessed beyond their intended lifecycle. The vulnerability is particularly dangerous because it allows a local attacker to leverage kernel memory management inconsistencies to escalate privileges to root level access. The technical nature of this issue stems from improper handling of sequence file operations within the kernel's block layer, where the stop function fails to properly validate the state of underlying data structures before attempting cleanup operations.
The operational impact of CVE-2016-7910 extends beyond simple privilege escalation as it provides attackers with a reliable method to gain elevated system privileges without requiring network access or external exploitation vectors. This local privilege escalation vulnerability operates at the kernel level, meaning that any user with access to the system can potentially exploit this flaw to execute arbitrary code with the highest possible privileges. The vulnerability's exploitation requires minimal prerequisites since it only necessitates local user access and does not depend on network connectivity or specific system configurations. Attackers can leverage this flaw to establish persistent backdoors, modify system files, or completely compromise the integrity of the affected system. The vulnerability's persistence across multiple kernel versions and its straightforward exploitation method make it particularly attractive to malicious actors seeking to gain unauthorized control over Linux systems.
Security professionals should recognize that CVE-2016-7910 aligns with several ATT&CK framework techniques including privilege escalation and defense evasion. The vulnerability specifically maps to T1068 (Local Privilege Escalation) and T1566 (Phishing) when considering how attackers might gain initial access to systems before exploiting this kernel flaw. From a CWE perspective, this vulnerability corresponds to CWE-416, which describes the use of freed memory condition, and CWE-362, which covers concurrent execution issues. The flaw demonstrates how improper resource management in kernel space can create exploitable conditions that bypass traditional security controls. Organizations should implement immediate patching strategies to address this vulnerability, as the window for exploitation remains open for systems running affected kernel versions. Additionally, system administrators should monitor for potential exploitation attempts through log analysis and implement proper access controls to limit local user privileges where possible. The vulnerability also highlights the importance of kernel hardening techniques and regular security assessments to identify similar flaws in system components that could provide similar escalation paths.