1) Insecure Default Variable Initialization

EUVDB-ID: #VU60267

Risk: Medium

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-41840

CWE-ID: CWE-453 - Insecure Default Variable Initialization

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to the SMM (System Management Mode) branch that registers a SWSMI handler does not sufficiently check or validate the allocated table variable EFI_BOOT_SERVICES. A remote authenticated attacker can overwrite the LocateProtocol or Freepool and execute arbitrary code on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

SdHostDriver: before 5.4: 05.40.35, 5.3: 05.32.35, 5.2: 05.23.35

---

CPE2.3

• cpe:2.3:h:insyde_software:sdhostdriver:*:*:*:*:*:*:*:*
• Full software list in CPE2.3 format available after registration.

External links

http://www.insyde.com/security-pledge

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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