CVE-2021-20322 – kernel: new DNS Cache Poisoning Attack based on ICMP fragment needed packets replies

https://notcve.org/view.php?id=CVE-2021-20322

A flaw in the processing of received ICMP errors (ICMP fragment needed and ICMP redirect) in the Linux kernel functionality was found to allow the ability to quickly scan open UDP ports. This flaw allows an off-path remote user to effectively bypass the 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. Se encontró un fallo en el procesamiento de los errores ICMP recibidos (fragmento ICMP necesario y redireccionamiento ICMP) en la funcionalidad del kernel de Linux que permite la capacidad de escanear rápidamente los puertos UDP abiertos. Este fallo permite a un usuario remoto fuera de la ruta de acceso omitir efectivamente la aleatorización del puerto de origen UDP. • https://bugzilla.redhat.com/show_bug.cgi?id=2014230 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.15-rc6&id=4785305c05b25a242e5314cc821f54ade4c18810 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.15-rc6&id=6457378fe796815c973f631a1904e147d6ee33b1 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/ipv4/route.c?h=v5.15-rc6&id=67d6d681e15b578c1725bad8ad079e05d1c48a8e https://git.kernel.org/pub/scm/linux/ke • CWE-330: Use of Insufficiently Random Values •