Vulnerability identifier: #VU53639

Vulnerability risk: Medium

CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:U/RC:C]

CVE-ID: CVE-2021-20591

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
MELSEC iQ-R 00 CPU
Hardware solutions / Firmware
MELSEC iQ-R 01 CPU
Hardware solutions / Firmware
MELSEC iQ-R 02 CPU
Hardware solutions / Firmware
MELSEC iQ-R 04 (EN) CPU
Hardware solutions / Firmware
MELSEC iQ-R 08 (EN) CPU
Hardware solutions / Firmware
MELSEC iQ-R 16 (EN) CPU
Hardware solutions / Firmware
MELSEC iQ-R 32 (EN) CPU
Hardware solutions / Firmware
MELSEC iQ-R 120 (EN) CPU
Hardware solutions / Firmware
MELSEC iQ-R 08 SFCPU
Hardware solutions / Firmware
MELSEC iQ-R 16 SFCPU
Hardware solutions / Firmware
MELSEC iQ-R 32 SFCPU
Hardware solutions / Firmware
MELSEC iQ-R 120 SFCPU
Hardware solutions / Firmware
MELSEC iQ-R 32 PCPU
Hardware solutions / Firmware
MELSEC iQ-R 16 PCPU
Hardware solutions / Firmware
MELSEC iQ-R 08 PCPU
Hardware solutions / Firmware
MELSEC iQ-R 120 PSFCPU
Hardware solutions / Firmware
MELSEC iQ-R 32 PSFCPU
Hardware solutions / Firmware
MELSEC iQ-R 16 PSFCPU
Hardware solutions / Firmware
MELSEC iQ-R 08 PSFCPU
Hardware solutions / Firmware

Vendor: Mitsubishi Electric

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper session management. A remote attacker can trigger resource exhaustion and perform a denial of service (DoS) attack.

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

MELSEC iQ-R 00 CPU: All versions

MELSEC iQ-R 01 CPU: All versions

MELSEC iQ-R 02 CPU: All versions

MELSEC iQ-R 04 (EN) CPU: All versions

MELSEC iQ-R 08 (EN) CPU: All versions

MELSEC iQ-R 16 (EN) CPU: All versions

MELSEC iQ-R 32 (EN) CPU: All versions

MELSEC iQ-R 120 (EN) CPU: All versions

MELSEC iQ-R 08 SFCPU: All versions

MELSEC iQ-R 16 SFCPU: All versions

MELSEC iQ-R 32 SFCPU: All versions

MELSEC iQ-R 120 SFCPU: All versions

MELSEC iQ-R 32 PCPU: All versions

MELSEC iQ-R 16 PCPU: All versions

MELSEC iQ-R 08 PCPU: All versions

MELSEC iQ-R 120 PSFCPU: All versions

MELSEC iQ-R 32 PSFCPU: All versions

MELSEC iQ-R 16 PSFCPU: All versions

MELSEC iQ-R 08 PSFCPU: All versions

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External links
http://ics-cert.us-cert.gov/advisories/icsa-21-147-05

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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.