Red Hat Enterprise Linux 7 update for kernel-alt

1) Use-after-free

EUVDB-ID: #VU51897

Risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-15436

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

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

The vulnerability exists due to a use-after-free error in fs/block_dev.c in the Linux kernel. A local user can run a specially crafted program to escalate privileges on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for IBM System z (Structure A): 7.0

Red Hat Enterprise Linux for Power 9: 7.0

kernel-alt (Red Hat package): before 4.14.0-115.35.1.el7a

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_system_z_structure_a:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_9:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:kernel-alt_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2021:0354

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Cleartext transmission of sensitive information

EUVDB-ID: #VU52058

Risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-1749

CWE-ID: CWE-319 - Cleartext Transmission of Sensitive Information

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to incorrect implementation of some networking protocols in IPsec, such as VXLAN and GENEVE tunnels over IPv6. When an encrypted tunnel is created between two hosts, the kernel isn't correctly routing tunneled data over the encrypted link; rather sending the data unencrypted. This would allow anyone in between the two endpoints to read the traffic unencrypted.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for IBM System z (Structure A): 7.0

Red Hat Enterprise Linux for Power 9: 7.0

kernel-alt (Red Hat package): before 4.14.0-115.35.1.el7a

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_system_z_structure_a:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_9:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:kernel-alt_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2021:0354

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Improper locking

EUVDB-ID: #VU51543

Risk: Low

CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2020-29661

CWE-ID: CWE-667 - Improper Locking

Exploit availability: Yes

Description

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

The vulnerability exists due to locking error in the tty subsystem of the Linux kernel in drivers/tty/tty_jobctrl.c. An local user can exploit this vulnerability to trigger a use-after-free error against TIOCSPGRP and execute arbitrary code with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for IBM System z (Structure A): 7.0

Red Hat Enterprise Linux for Power 9: 7.0

kernel-alt (Red Hat package): before 4.14.0-115.35.1.el7a

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_system_z_structure_a:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_9:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:kernel-alt_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2021:0354

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.