Information disclosure in Linux kernel

1) Improper locking

EUVDB-ID: #VU57039

Risk: Low

CVSSv3.1: 3.9 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-29660

CWE-ID: CWE-667 - Improper Locking

Exploit availability: No

Description

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to double-locking error in drivers/tty/tty_io.c and drivers/tty/tty_jobctrl.c. An authenticated local user can exploit this vulnerability to perform a read-after-free attack against TIOCGSID and gain access to sensitive information.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.9.14

External links

http://www.openwall.com/lists/oss-security/2020/12/10/1
http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c8bcd9c5be24fb9e6132e97da5a35e55a83e36b9
http://lists.debian.org/debian-lts-announce/2021/02/msg00018.html
http://lists.debian.org/debian-lts-announce/2021/03/msg00010.html
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BOB25SU6XUL4TNP7KB63WNZSYTIYFDPP/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MZ7OAKAEFAXQRGBZK4LYUWINCD3D2XCL/
http://security.netapp.com/advisory/ntap-20210122-0001/
http://www.debian.org/security/2021/dsa-4843

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?

No. We are not aware of malware exploiting this vulnerability.