Vulnerability identifier: #VU7694

Vulnerability risk: Medium

CVSSv3.1: 8.4 [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]

CVE-ID: CVE-2017-7533

CWE-ID: CWE-362

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

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.

Mitigation
Install update from vendor's repository.

Vulnerable software versions

Linux kernel: 4.12.1 - 4.12.4

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External links
http://openwall.com/lists/oss-security/2017/08/03/2
http://bugzilla.redhat.com/show_bug.cgi?id=1468283
http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1408967.html
http://patchwork.kernel.org/patch/9755753/
http://patchwork.kernel.org/patch/9755757/
http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=49d31c2f389acfe8341708...

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.