CVE-2018-10880 in Android
Summary
by MITRE
Linux kernel is vulnerable to a stack-out-of-bounds write in the ext4 filesystem code when mounting and writing to a crafted ext4 image in ext4_update_inline_data(). An attacker could use this to cause a system crash and a denial of service.
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Analysis
by VulDB Data Team • 07/04/2023
The vulnerability identified as CVE-2018-10880 represents a critical stack-based buffer overflow in the linux kernel's ext4 filesystem implementation. This flaw exists within the ext4_update_inline_data() function which handles inline data updates for ext4 filesystems. The vulnerability arises during the mounting and writing operations on specially crafted ext4 image files, creating a condition where the kernel attempts to write beyond the bounds of a stack-allocated buffer. The technical nature of this issue places it squarely within the category of improper restriction of operations within a bounded buffer as classified by CWE-121, and more specifically aligns with CWE-787 which addresses out-of-bounds write conditions. This type of vulnerability is particularly dangerous because it can be exploited to trigger a system crash or denial of service condition, effectively rendering the affected system non-functional.
The operational impact of CVE-2018-10880 extends beyond simple system instability to encompass potential exploitation for more sophisticated attacks. When an attacker successfully crafts an ext4 image that triggers this vulnerability, the kernel's stack-based buffer overflow can cause unpredictable behavior including kernel panics, system crashes, and complete denial of service for the affected system. The vulnerability is particularly concerning because it operates at the kernel level, meaning that exploitation does not require elevated privileges or specific user context to trigger the condition. This makes the attack surface significantly broader compared to user-space vulnerabilities. The exploitation process involves creating a malicious ext4 filesystem image that when mounted and written to, causes the kernel to execute the vulnerable code path, leading to the out-of-bounds write condition. According to ATT&CK framework, this vulnerability could be categorized under T1499.004 which covers Network Denial of Service, and potentially T1068 which involves Exploitation for Privilege Escalation, though the latter would require additional attack vectors to be fully realized.
Mitigation strategies for CVE-2018-10880 should focus on immediate kernel updates and system hardening measures. The most effective immediate solution involves applying the relevant kernel security patches provided by the linux kernel maintainers and distribution vendors. These patches typically include bounds checking mechanisms and proper validation of input parameters before buffer operations occur. System administrators should also implement monitoring solutions to detect unusual mounting operations or filesystem access patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing filesystem-level restrictions to prevent mounting of untrusted or unverified ext4 images, particularly in environments where security is paramount. The vulnerability's nature makes it particularly susceptible to exploitation through malicious USB drives, network shares, or any storage medium that might contain crafted ext4 filesystems. Regular system audits and vulnerability scanning should include checks for unpatched kernel versions, as this vulnerability was addressed in kernel versions released after the initial discovery. Network segmentation and access controls should be strengthened to limit potential attack vectors that could deliver malicious ext4 images to vulnerable systems. The remediation process should also include comprehensive testing of patched systems to ensure that the vulnerability has been properly addressed without introducing regressions in system functionality.