SB2021032009 - Amazon Linux AMI update for kernel
Published: March 20, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 7 secuirty vulnerabilities.
1) Resource management error (CVE-ID: CVE-2021-26930)
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to improper management of internal resources when processing service requests to the PV backend within drivers/block/xen-blkback/blkback.c driver in Xen. A local user on the guest OS can perform a denial of service (DoS) attack.
2) Allocation of resources without limits or throttling (CVE-ID: CVE-2021-26931)
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to allocation of resources without limits or throttling error within the scsiback_gnttab_data_map_batch() function in drivers/xen/xen-scsiback.c. A local user can perform a denial of service (DoS) attack.
3) Buffer overflow (CVE-ID: CVE-2021-26932)
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to memory corruption within the gntdev_map_grant_pages() function in drivers/xen/gntdev.c. A local user can perform a denial of service (DoS) attack.
4) Information disclosure (CVE-ID: CVE-2021-27363)
The vulnerability allows a local user to gain access to potentially sensitive information.
The vulnerability exists due to the show_transport_handle() shows iSCSI transport handle to non-root users. A local user can gain unauthorized access to sensitive information and use it along with another vulnerability, such as #VU51452, to escalate privileges on the system.
5) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-27364)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to iscsi_if_recv_msg() allows non-root users to connect and send commands to the Linux kernel. A local user can escalate privileges on the system.
6) Buffer overflow (CVE-ID: CVE-2021-27365)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error when processing Netlink messages in Linux kernel through 5.11.3, as certain iSCSI data structures do not have appropriate length constraints or checks, and can exceed the PAGE_SIZE value. A local unprivileged user can send a Netlink message that is associated with iSCSI, and has a length up to the maximum length of a Netlink message, trigger memory corruption and execute arbitrary code on the system with elevated privileges.
7) Allocation of resources without limits or throttling (CVE-ID: CVE-2021-28038)
The vulnerability allows a local user to a crash the entire system.
The vulnerability exists due to allocation of resources without limits or throttling error within the xenvif_tx_action() function in drivers/net/xen-netback/netback.c. A local user can a crash the entire system.
Remediation
Install update from vendor's website.