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. Kernel versions before 5.10 may be vulnerable to this issue.

A flaw in ICMP packets in the Linux kernel may allow an attacker to quickly scan open UDP ports. This flaw allows an off-path remote attacker to effectively bypass source port UDP randomization. Software that relies on UDP source port randomization are indirectly affected as well on the Linux Based Products (RUGGEDCOM RM1224: All versions between v5.0 and v6.4, SCALANCE M-800: All versions between v5.0 and v6.4, SCALANCE S615: All versions between v5.0 and v6.4, SCALANCE SC-600: All versions prior to v2.1.3, SCALANCE W1750D: v8.3.0.1, v8.6.0, and v8.7.0, SIMATIC Cloud Connect 7: All versions, SIMATIC MV500 Family: All versions, SIMATIC NET CP 1243-1 (incl. SIPLUS variants): Versions 3.1.39 and later, SIMATIC NET CP 1243-7 LTE EU: Version

https://us-cert.cisa.gov/ics/advisories/icsa-21-131-03 [No Types Assigned]

https://bugzilla.redhat.com/show_bug.cgi?id=1894579 [Issue Tracking, Patch, Third Party Advisory]

https://cert-portal.siemens.com/productcert/pdf/ssa-324955.pdf [No Types Assigned]

https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html [No Types Assigned]

https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html [No Types Assigned]

https://security.netapp.com/advisory/ntap-20201210-0002/ [No Types Assigned]