Red Hat Enterprise Linux 7.2 update for grub2
| Risk | Low |
| Patch available | YES |
| Number of vulnerabilities | 7 |
| CVE-ID | CVE-2020-14372 CVE-2020-25632 CVE-2020-25647 CVE-2020-27749 CVE-2020-27779 CVE-2021-20225 CVE-2021-20233 |
| CWE-ID | CWE-264 CWE-416 CWE-787 CWE-121 CWE-285 |
| Exploitation vector | Local |
| Public exploit |
Public exploit code for vulnerability #1 is available. Public exploit code for vulnerability #2 is available. Public exploit code for vulnerability #7 is available. |
| Vulnerable software Subscribe |
Red Hat Enterprise Linux Server - AUS Operating systems & Components / Operating system grub2 (Red Hat package) Operating systems & Components / Operating system package or component |
| Vendor | Red Hat Inc. |
Security Bulletin
This security bulletin contains information about 7 vulnerabilities.
1) Security restrictions bypass
EUVDB-ID: #VU51187
Risk: Low
CVSSv3.1: 5.8 [CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]
CVE-ID: CVE-2020-14372
CWE-ID:
CWE-264 - Permissions, Privileges, and Access Controls
Exploit availability: Yes
DescriptionThe vulnerability allows a local privileged user to bypass implemented security restrictions.
The vulnerability exists due to GRUB enables usage of the acpi command even when Secure Boot is enabled by firmware. A local user with root privileges can put a small SSDT into /boot/efi folder and modify the grub.cfg file to load that SSDT during kernel boot. The SSDT then gets run by the kernel and it overwrites the kernel lock down configuration enabling the attacker to load unsigned kernel modules and kexec unsigned code.
Install updates from vendor's website.
Red Hat Enterprise Linux Server - AUS: 7.2
grub2 (Red Hat package): before 2.02-0.86.el7_2.2
CPE2.3 External linkshttp://access.redhat.com/errata/RHSA-2021:0704
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.
2) Use-after-free
EUVDB-ID: #VU51188
Risk: Low
CVSSv3.1: 6 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]
CVE-ID: CVE-2020-25632
CWE-ID:
CWE-416 - Use After Free
Exploit availability: Yes
DescriptionThe vulnerability allows a local user to bypass implemented security restrictions.
The vulnerability exists due to a use-after-free error when handling module unloads. A local privileged user can unload a kernel module, trigger a use-after-free error and bypass Secure Boot protection mechanism.
Install updates from vendor's website.
Red Hat Enterprise Linux Server - AUS: 7.2
grub2 (Red Hat package): before 2.02-0.86.el7_2.2
CPE2.3 External linkshttp://access.redhat.com/errata/RHSA-2021:0704
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.
3) Out-of-bounds write
EUVDB-ID: #VU51189
Risk: Low
CVSSv3.1: 5.9 [CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2020-25647
CWE-ID:
CWE-787 - Out-of-bounds write
Exploit availability: No
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error when processing untrusted input from USB device in grub_usb_device_initialize(). An attacker with physical access to the system can trigger an out-of-bounds write error with a malicious USB drive, bypass Secure Boot protection and execute arbitrary code on the system with elevated privileges.
Install updates from vendor's website.
Red Hat Enterprise Linux Server - AUS: 7.2
grub2 (Red Hat package): before 2.02-0.86.el7_2.2
CPE2.3 External linkshttp://access.redhat.com/errata/RHSA-2021:0704
Q & A
Can this vulnerability be exploited remotely?
No. The attacker should have physical access to the system in order to successfully exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
4) Stack-based buffer overflow
EUVDB-ID: #VU51193
Risk: Low
CVSSv3.1: 5.8 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2020-27749
CWE-ID:
CWE-121 - Stack-based buffer overflow
Exploit availability: No
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error within the grub_parser_split_cmdline() function while expanding variable names present in the supplied command line in to their corresponding variable contents. A local privileged user can run a specially crafted program to trigger the stack-based buffer overflow and bypass Secure Boot protection.
Install updates from vendor's website.
Red Hat Enterprise Linux Server - AUS: 7.2
grub2 (Red Hat package): before 2.02-0.86.el7_2.2
CPE2.3 External linkshttp://access.redhat.com/errata/RHSA-2021:0704
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.
5) Improper Authorization
EUVDB-ID: #VU51194
Risk: Low
CVSSv3.1: 6.1 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2020-27779
CWE-ID:
CWE-285 - Improper Authorization
Exploit availability: No
DescriptionThe vulnerability allows a local user to bypass authorization checks.
The vulnerability exists within the cutmem command, which does not honor the Secure Boot locking. A local privileged user can remove address ranges from memory creating an opportunity to circumvent Secure Boot protections after proper triage about grub's memory layout.
Install updates from vendor's website.
Red Hat Enterprise Linux Server - AUS: 7.2
grub2 (Red Hat package): before 2.02-0.86.el7_2.2
CPE2.3 External linkshttp://access.redhat.com/errata/RHSA-2021:0704
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.
6) Out-of-bounds write
EUVDB-ID: #VU51197
Risk: Low
CVSSv3.1: 5.6 [CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-20225
CWE-ID:
CWE-787 - Out-of-bounds write
Exploit availability: No
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error within the option parser. A local privileged user can write past the end of a heap-allocated buffer by calling certain commands with a large number of specific short forms of options and execute arbitrary code with elevated privileges.
Install updates from vendor's website.
Red Hat Enterprise Linux Server - AUS: 7.2
grub2 (Red Hat package): before 2.02-0.86.el7_2.2
CPE2.3 External linkshttp://access.redhat.com/errata/RHSA-2021:0704
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.
7) Out-of-bounds write
EUVDB-ID: #VU51198
Risk: Low
CVSSv3.1: 5.8 [CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]
CVE-ID: CVE-2021-20233
CWE-ID:
CWE-787 - Out-of-bounds write
Exploit availability: Yes
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error within the setparam_prefix() function in menu rendering code. A local privileged user can run a specially crafted program to trigger out-of-bounds write and escalate privileges on the system.
Install updates from vendor's website.
Red Hat Enterprise Linux Server - AUS: 7.2
grub2 (Red Hat package): before 2.02-0.86.el7_2.2
CPE2.3 External linkshttp://access.redhat.com/errata/RHSA-2021:0704
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.
