Zero-day vulnerability in Linux kernel

Race condition
CVE-2017-7533

Vulnerability details

Advisory: SB2017080701 - Privilege escalation in Linux kernel

Vulnerable component: Linux kernel

CVE-ID: CVE-2017-7533

CVSSv3 score: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Description:

The vulnerability allows a local user to execute arbitrary code with escalated privileges.

The vulnerability exists due to a race condition in the fsnotify implementation in the Linux kernel through 4.12.4. A local user can create an application, which leverages simultaneous execution of the inotify_handle_event and vfs_rename functions and trigger memory corruption and denials of service attack or execute arbitrary code on the target system with root privileges.

Successful exploitation of this vulnerability may allow a local user to obtain elevated privileges on the system.

Note: this vulnerability is being active exploited in the wild for 32-bit systems in August 2017.

Public Exploits:

- Linux Kernel < 3.16.39 (Debian 8 x64) - 'inotfiy' Local Privilege Escalation [Exploit-DB]

External links:

http://openwall.com/lists/oss-security/2017/08/03/2
https://bugzilla.redhat.com/show_bug.cgi?id=1468283

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.