SB2021021727 - Amazon Linux AMI update for kernel
Published: February 17, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Use-after-free (CVE-ID: CVE-2020-27825)
The vulnerability allows a local user to compromise vulnerable system.
The vulnerability exists due to a use-after-free error in kernel/trace/ring_buffer.c in Linux kernel, when trace_open and resize of cpu buffer are running in parallel on different CPUs. A local user can run a specially crafted application and perform a denial of service attack or read contentsof kernel memory.
2) Path traversal (CVE-ID: CVE-2020-28374)
The vulnerability allows a remote user to perform directory traversal attacks.
The vulnerability exists due to input validation error when processing directory traversal sequences in drivers/target/target_core_xcopy.c in the Linux kernel. A remote user with access to iSCSI LUN can send a specially crafted XCOPY request and read or write arbitrary files on the system.
3) Use-after-free (CVE-ID: CVE-2021-3347)
The vulnerability allows a local user to elevate privileges on the system.
The vulnerability exists due to a use-after-free error when handling PI futexes. A local user can run a specially crafted program to trigger a use-after-free error and execute arbitrary code with elevated privileges.
4) Use-after-free (CVE-ID: CVE-2021-3348)
The vulnerability allows a local authenticated user to escalate privileges on the system.
The vulnerability exists due to a use-after-free error within the nbd_add_socket in drivers/block/nbd.c. A local authenticated user can trigger a use-after-free error and escalate privileges on the system.
Remediation
Install update from vendor's website.