#VU58088 Improper Null Termination in Siemens products - CVE-2021-31888

Vulnerability identifier: #VU58088

Vulnerability risk: Medium

CVSSv4.0: 6.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-31888

CWE-ID: CWE-170

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Nucleus NET
Server applications / Other server solutions
Nucleus Source Code
Server applications / Other server solutions
Capital VSTAR
Server applications / Other server solutions
Nucleus ReadyStart
Server applications / Other server solutions

Vendor: Siemens

Description

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

The vulnerability exists due to improper null termination when the FTP server does not properly validate the length of the “MKD/XMKD” command. A remote authenticated attacker can execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nucleus NET: All versions

Nucleus Source Code: All versions

Capital VSTAR: All versions

Nucleus ReadyStart: before 4.1.1

---

External links
https://cert-portal.siemens.com/productcert/pdf/ssa-044112.pdf

---

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.