#VU49150 Use of insufficiently random values in Linux kernel - CVE-2020-25705

Vulnerability identifier: #VU49150

Vulnerability risk: Medium

CVSSv4.0: 5.5 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2020-25705

CWE-ID: CWE-330

Exploitation vector: Network

Exploit availability: Yes

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

Vendor: Linux Foundation

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

A flaw in the way reply ICMP packets are limited in the Linux kernel functionality was found that allows to quickly scan open UDP ports. This flaw allows an off-path remote user to effectively bypassing source port UDP randomization. The highest threat from this vulnerability is to confidentiality and possibly integrity, because software that relies on UDP source port randomization are indirectly affected as well.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.10, 5.10

---

External links
https://bugzilla.redhat.com/show_bug.cgi?id=1894579
https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html
https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html
https://security.netapp.com/advisory/ntap-20201210-0002/

---

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. However, proof of concept for this vulnerability is available.