Device tracking vulnerability via UDP in Linux kernel

1) Information disclosure

EUVDB-ID: #VU51269

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-18282

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote attacker to track devices via UDP packets.

The vulnerability exists due to excessive data output in the flow_dissector feature in the Linux kernel 4.3 through 5.x before 5.3.10 and affects net/core/flow_dissector.c and related code. The auto flowlabel of a UDP IPv6 packet relies on a 32-bit hashrnd value as a secret, and because jhash (instead of siphash) is used. The hashrnd value remains the same starting from boot time, and can be inferred by an attacker. A remote attacker can use the hashrnd value and track reliably track activity of devices using UDP packets.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.3.10

External links

http://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.3.10
http://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=55667441c84fa5e0911a0aac44fb059c15ba6da2
http://lists.debian.org/debian-lts-announce/2020/03/msg00001.html
http://security.netapp.com/advisory/ntap-20200204-0002/
http://www.computer.org/csdl/proceedings-article/sp/2020/349700b594/1j2LgrHDR2o

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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