#VU15987 Insufficient verification of data authenticity in Modicon M221 - CVE-2018-7798

Vulnerability identifier: #VU15987

Vulnerability risk: Low

CVSSv4.0: 6.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-7798

CWE-ID: CWE-345

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Modicon M221
Hardware solutions / Firmware

Vendor: Schneider Electric

Description

The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The vulnerability exists due to improper implementation of the network configuration module in UMAS protocol. A remote attacker can modify configuration parameters and intercept a target PLC’s network traffic.

Mitigation

Schneider Electric recommends the following mitigations to reduce the risk:

• Set up a firewall blocking all remote/external access to Port 502. 
• Within the Modicon M221 application, users should disable all unused protocols, especially programming protocol, as described in section “Configuring Ethernet Network” of SoMachine Basic online help. This will prevent remote programming of the M221 PLC.

Vulnerable software versions

Modicon M221: All versions

---

External links
https://download.schneider-electric.com/files?p_enDocType=Technical+leaflet&p_File_Name=SEVD...

---

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.