Ubuntu 20.04 LTS / 20.10 : Linux kernel vulnerabilities (USN-4999-1)

high Nessus Plugin ID 150954
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Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 20.04 LTS / 20.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4999-1 advisory.

- The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent Privacy (WEP) doesn't require that received fragments be cleared from memory after (re)connecting to a network. Under the right circumstances, when another device sends fragmented frames encrypted using WEP, CCMP, or GCMP, this can be abused to inject arbitrary network packets and/or exfiltrate user data.
(CVE-2020-24586)

- The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent Privacy (WEP) doesn't require that all fragments of a frame are encrypted under the same key. An adversary can abuse this to decrypt selected fragments when another device sends fragmented frames and the WEP, CCMP, or GCMP encryption key is periodically renewed. (CVE-2020-24587)

- The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent Privacy (WEP) doesn't require that the A-MSDU flag in the plaintext QoS header field is authenticated.
Against devices that support receiving non-SSP A-MSDU frames (which is mandatory as part of 802.11n), an adversary can abuse this to inject arbitrary network packets. (CVE-2020-24588)

- A vulnerability was found in Linux Kernel where refcount leak in llcp_sock_bind() causing use-after-free which might lead to privilege escalations. (CVE-2020-25670)

- A vulnerability was found in Linux Kernel, where a refcount leak in llcp_sock_connect() causing use-after- free which might lead to privilege escalations. (CVE-2020-25671)

- A memory leak vulnerability was found in Linux kernel in llcp_sock_connect (CVE-2020-25672)

- A vulnerability was found in Linux kernel where non-blocking socket in llcp_sock_connect() leads to leak and eventually hanging-up the system. (CVE-2020-25673)

- An issue was discovered in the kernel in NetBSD 7.1. An Access Point (AP) forwards EAPOL frames to other clients even though the sender has not yet successfully authenticated to the AP. This might be abused in projected Wi-Fi networks to launch denial-of-service attacks against connected clients and makes it easier to exploit other vulnerabilities in connected clients. (CVE-2020-26139)

- An issue was discovered in the ALFA Windows 10 driver 6.1316.1209 for AWUS036H. The Wi-Fi implementation does not verify the Message Integrity Check (authenticity) of fragmented TKIP frames. An adversary can abuse this to inject and possibly decrypt packets in WPA or WPA2 networks that support the TKIP data- confidentiality protocol. (CVE-2020-26141)

- An issue was discovered on Samsung Galaxy S3 i9305 4.4.4 devices. The WEP, WPA, WPA2, and WPA3 implementations accept second (or subsequent) broadcast fragments even when sent in plaintext and process them as full unfragmented frames. An adversary can abuse this to inject arbitrary network packets independent of the network configuration. (CVE-2020-26145)

- An issue was discovered in the Linux kernel 5.8.9. The WEP, WPA, WPA2, and WPA3 implementations reassemble fragments even though some of them were sent in plaintext. This vulnerability can be abused to inject packets and/or exfiltrate selected fragments when another device sends fragmented frames and the WEP, CCMP, or GCMP data-confidentiality protocol is used. (CVE-2020-26147)

- A race condition in Linux kernel SCTP sockets (net/sctp/socket.c) before 5.12-rc8 can lead to kernel privilege escalation from the context of a network service or an unprivileged process. 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 an attacker 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. (CVE-2021-23133)

- An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations. (CVE-2021-29155)

- This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel 5.11.15. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the handling of eBPF programs. The issue results from the lack of proper validation of user-supplied eBPF programs prior to executing them.
An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the kernel. Was ZDI-CAN-13661. (CVE-2021-31440)

- kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads, leading to disclosure of stack content via side-channel attacks, aka CID-801c6058d14a. The specific concern is not protecting the BPF stack area against speculative loads. Also, the BPF stack can contain uninitialized data that might represent sensitive information previously operated on by the kernel. (CVE-2021-31829)

- kernel/bpf/verifier.c in the Linux kernel through 5.12.7 enforces incorrect limits for pointer arithmetic operations, aka CID-bb01a1bba579. This can be abused to perform out-of-bounds reads and writes in kernel memory, leading to local privilege escalation to root. In particular, there is a corner case where the off reg causes a masking direction change, which then results in an incorrect final aux->alu_limit.
(CVE-2021-33200)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-4999-1

Plugin Details

Severity: High

ID: 150954

File Name: ubuntu_USN-4999-1.nasl

Version: 1.2

Type: local

Agent: unix

Published: 6/23/2021

Updated: 6/23/2021

Dependencies: ssh_get_info.nasl, linux_alt_patch_detect.nasl

Risk Information

CVSS Score Source: CVE-2021-33200

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.10, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-1029-raspi, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-1029-raspi-nolpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-1030-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-1033-oracle, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-1035-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-1036-azure, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-1038-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-59-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-59-generic-64k, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-59-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-59-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-azure, p-cpe:/a:canonical:ubuntu_linux:linux-image-azure-edge, p-cpe:/a:canonical:ubuntu_linux:linux-image-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-gcp-edge, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-64k, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-64k-hwe-20.04, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-64k-hwe-20.04-edge, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-hwe-20.04, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-hwe-20.04-edge, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-hwe-20.04, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-hwe-20.04-edge, p-cpe:/a:canonical:ubuntu_linux:linux-image-gke, p-cpe:/a:canonical:ubuntu_linux:linux-image-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-hwe-20.04, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-hwe-20.04-edge, p-cpe:/a:canonical:ubuntu_linux:linux-image-oem-20.04, p-cpe:/a:canonical:ubuntu_linux:linux-image-oracle, p-cpe:/a:canonical:ubuntu_linux:linux-image-oracle-edge, p-cpe:/a:canonical:ubuntu_linux:linux-image-raspi, p-cpe:/a:canonical:ubuntu_linux:linux-image-raspi-nolpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-hwe-20.04, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-hwe-20.04-edge

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 6/23/2021

Vulnerability Publication Date: 4/14/2021

Reference Information

CVE: CVE-2020-24586, CVE-2020-24587, CVE-2020-24588, CVE-2020-25670, CVE-2020-25671, CVE-2020-25672, CVE-2020-25673, CVE-2020-26139, CVE-2020-26141, CVE-2020-26145, CVE-2020-26147, CVE-2021-3609, CVE-2021-23133, CVE-2021-29155, CVE-2021-31440, CVE-2021-31829, CVE-2021-33200

USN: 4999-1