SB2021062328 - Ubuntu update for linux

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) Race condition (CVE-ID: CVE-2021-3609)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition in the CAN BCM networking protocol (net/can/bcm.c) in the Linux kernel ranging from version 2.6.25 to mainline 5.13-rc6. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.

2) Out-of-bounds read (CVE-ID: CVE-2021-3600)

The vulnerability allows a local user to execute arbitrary code.

The vulnerability exists due to out-of-bounds read error within the fixup_bpf_calls() function in kernel/bpf/verifier.c. A local user can execute arbitrary code.

3) Race condition (CVE-ID: CVE-2021-23133)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition in Linux kernel SCTP sockets (net/sctp/socket.c). If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock then an element is removed from the auto_asconf_splist list without any proper locking. This can be exploited by a local user with network service privileges to escalate to root or from the context of an unprivileged user directly if a BPF_CGROUP_INET_SOCK_CREATE is attached which denies creation of some SCTP socket.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-5003-1