{"id":76196,"date":"2020-03-31T19:42:05","date_gmt":"2020-03-31T17:42:05","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf"},"modified":"2020-03-31T19:42:05","modified_gmt":"2020-03-31T17:42:05","slug":"uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sv\/blog\/news\/uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf","title":{"rendered":"En s\u00e5rbarhet i Linux-k\u00e4rnan som m\u00f6jligg\u00f6r att man kan h\u00f6ja sina privilegier via BPF","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Publicerade<\/a><\/noindex> information about the vulnerability (CVE-2020-8835<\/a><\/noindex>) in the Linux kernel, which was used in a competition Pwn2Own 2020<\/a><\/noindex> during a demonstration of hacking Ubuntu. The vulnerability allowed an unprivileged user to gain root rights. A working exploit exists but has not yet been published. The vulnerability is present in the eBPF subsystem, which allows handlers for tracing, analyzing the operation of subsystems, and managing traffic to be executed within the kernel in a special virtual machine with JIT.<\/p>\n

The problem is caused by an error in the __reg_bound_offset32() function used to check 32-bit operations in BPF bytecode. Due to incorrect boundary calculations of the register, conditions arose for reading and writing data outside the allocated buffer in the kernel memory when processing specially crafted BPF applications. This issue appeared in kernel 5.5 and later, when backported fixes were carried over to kernel 5.4, as well as into the kernel 5.3 package<\/a><\/noindex>, offered in Ubuntu Linux.<\/p>\n

To block the vulnerability, it is recommended to rollback<\/a><\/noindex> the problematic patch or prohibit the execution of BPF applications by unprivileged users by setting sysctl kernel.unprivileged_bpf_disabled to 1. Status of the fix in distributions: Ubuntu<\/a><\/noindex>, Debian<\/a><\/noindex>, Arch<\/a><\/noindex>, Fedora<\/a><\/noindex> och SUSE<\/a><\/noindex> (in the kernel RHEL<\/a><\/noindex> the problematic change was not carried over).<\/p>\n

<\/a><\/noindex><\/p>\n

K\u00e4lla: opennet.ru<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

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