CVE-2016-1583 in Android
Summary
by MITRE • 01/25/2023
The ecryptfs_privileged_open function in fs/ecryptfs/kthread.c in the Linux kernel before 4.6.3 allows local users to gain privileges or cause a denial of service (stack memory consumption) via vectors involving crafted mmap calls for /proc pathnames, leading to recursive pagefault handling.
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Analysis
by VulDB Data Team • 11/05/2024
The vulnerability identified as CVE-2016-1583 resides within the Linux kernel's eCryptfs implementation, specifically in the ecryptfs_privileged_open function located in fs/ecryptfs/kthread.c. This flaw represents a critical security issue that affects Linux kernel versions prior to 4.6.3, where local attackers can exploit the vulnerability to either escalate privileges or induce a denial of service condition. The vulnerability stems from improper handling of crafted mmap calls directed at /proc pathnames, creating a recursive pagefault scenario that consumes excessive stack memory resources.
The technical exploitation of this vulnerability occurs through a specific code path involving the eCryptfs kernel module's handling of privileged operations. When a local user crafts malicious mmap calls targeting /proc filesystem entries, the ecryptfs_privileged_open function fails to properly validate or handle these requests, leading to recursive pagefault handling mechanisms. This recursive behavior causes the kernel stack to consume excessive memory resources, ultimately resulting in either system crashes or privilege escalation opportunities. The vulnerability is particularly dangerous because it operates at the kernel level, where successful exploitation can provide attackers with elevated system privileges or the ability to crash the entire system.
From an operational impact perspective, this vulnerability creates significant risks for systems running affected Linux kernel versions. Local users who can execute code on the target system can leverage this flaw to either gain root privileges or cause system instability through denial of service conditions. The recursive pagefault handling mechanism consumes stack memory rapidly, potentially leading to kernel panics or system hangs that render the affected system unusable. This vulnerability is particularly concerning in multi-user environments where privilege escalation could allow attackers to compromise entire systems or access sensitive data. The impact extends beyond simple denial of service as the privilege escalation aspect could enable attackers to modify system files, install malware, or establish persistent access to compromised systems.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper handling of recursive operations in kernel space. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques through kernel exploits, specifically T1068 which covers 'Local Privilege Escalation' and T1499 which covers 'Endpoint Denial of Service'. The attack vector requires local system access, making it a post-compromise exploitation opportunity that can be leveraged by attackers who have already gained initial access to a system. Organizations should prioritize patching affected systems to address this vulnerability, as the kernel-level nature of the flaw makes it particularly dangerous and difficult to mitigate through traditional application-level security controls.
Mitigation strategies for CVE-2016-1583 focus primarily on immediate kernel version updates to 4.6.3 or later, which contain the necessary patches to address the recursive pagefault handling issue. System administrators should also implement monitoring for unusual mmap activity or recursive pagefault patterns that might indicate exploitation attempts. Additional defensive measures include restricting local user access where possible, implementing proper privilege separation, and maintaining up-to-date security monitoring solutions that can detect anomalous kernel behavior. Organizations should also conduct thorough vulnerability assessments to identify systems running affected kernel versions and prioritize remediation efforts accordingly, as the vulnerability can be exploited without requiring special privileges beyond local system access.