More than 25 mobile models computers of Lenovo are vulnerable to malicious attacks that disable the UEFI secure boot process and then run unsigned applications UEFI or load bootloaders for permanent backdoors on devices.
Την ίδια στιγμή που ερευνητές από την εταιρεία ασφαλείας ESET αποκάλυψαν τα τρωτά σημεία, ο κατασκευαστής φορητών υπολογιστών κυκλοφόρησε ενημερώσεις ασφαλείας για 25 μοντέλα, όπως τα ThinkPads, Yoga Slims και IdeaPads. Τα κενά ασφαλείας που υπονομεύουν την ασφαλή εκκίνηση του UEFI είναι σοβαρά επειδή επιτρέπουν στους εισβολείς να εγκαταστήσουν malicious firmware that survives operating system formats.
The Unified Extensible Firmware Interface, or UEFI is the software that bridges the firmware of a computer with its operating system. As the first track code which runs when a computer starts, is the first link in the security chain. Because UEFI resides on a flash chip on the motherboard, infections are very difficult to detect and remove.
Standard measures such as a hard disk format and reinstallation of the operating system do not help, because the infected UEFI will re-infect the computer when it starts.
ESET said that vulnerabilities CVE-2022-3430, CVE-2022-3431 and CVE-2022-3432 allow disabling UEFI Secure Boot or resetting the Secure Boot database (and dbx) to factory default settings. . Secure Boot uses databases to allow and deny mechanisms. The DBX database, in particular, stores encrypted hashes of denied keys.
Disabling or resetting databases to default values allows an attacker to override restrictions that would normally apply.