CVE-2017-10662 in Linux
Summary
by MITRE • 01/25/2023
The sanity_check_raw_super function in fs/f2fs/super.c in the Linux kernel before 4.11.1 does not validate the segment count, which allows local users to gain privileges via unspecified vectors.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2017-10662 resides within the Linux kernel's F2FS (Flash-Friendly File System) implementation, specifically in the sanity_check_raw_super function located in fs/f2fs/super.c. This flaw represents a critical security weakness that affects Linux kernel versions prior to 4.11.1, creating a potential privilege escalation vector for local attackers. The vulnerability stems from insufficient validation of segment count parameters during the superblock initialization process, which is fundamental to how F2FS manages flash storage devices and maintains file system integrity.
The technical root cause of this vulnerability lies in the absence of proper input validation within the sanity_check_raw_super function, which is responsible for verifying the integrity of the raw superblock data structure before the F2FS file system is mounted. When the segment count parameter is not properly validated, malicious local users can manipulate this value to bypass normal security checks and potentially corrupt the file system metadata. This weakness falls under the CWE-20 category of "Improper Input Validation" and represents a classic example of how inadequate parameter checking can lead to privilege escalation vulnerabilities. The flaw operates at the kernel level where file system operations are processed, making it particularly dangerous as it can be exploited without requiring network access or external attack vectors.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables local attackers to potentially corrupt file system structures, manipulate data integrity, and gain elevated system privileges. Attackers can exploit this weakness by crafting malicious F2FS superblock data with manipulated segment count values, which can then be processed during mount operations. This vulnerability is particularly concerning in environments where local users have access to systems running vulnerable kernel versions, as it can be leveraged to establish persistent access or escalate privileges to root level. The attack surface is broad given that F2FS is commonly used in embedded systems, mobile devices, and storage solutions where local privilege escalation can have significant consequences.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1068 which describes "Exploitation for Privilege Escalation" and can be classified under the broader category of kernel-level exploits. The attack requires local system access and leverages the kernel's failure to validate critical parameters during file system initialization. Mitigation strategies should focus on immediate kernel updates to version 4.11.1 or later, where the validation has been implemented to prevent malformed segment count values from being processed. System administrators should also consider implementing additional security measures such as restricting local user access to storage devices, monitoring for unusual file system mount operations, and ensuring proper kernel patch management protocols are in place to prevent similar vulnerabilities from being exploited in the future.