Improper Null Termination in Siemens products - CVE-2021-31887

Vulnerability identifier: #VU58087

CSH Severity: Medium

CVSS v4: 8.7 [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]

CVE-ID: CVE-2021-31887

CWE-ID: CWE-170

Exploitation vector: Remote access

Exploit availability: No public exploit available

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 “PWD/XPWD” command. A remote authenticated attacker can execute arbitrary code on the target system.

Nucleus NET
Nucleus Source Code
Capital VSTAR
Nucleus ReadyStart
APOGEE MBC (PPC) (BACnet)
APOGEE MBC (PPC) (P2 Ethernet)
APOGEE MEC (PPC) (BACnet)
APOGEE MEC (PPC) (P2 Ethernet)
APOGEE PXC Compact (BACnet)
APOGEE PXC Compact (P2 Ethernet)
APOGEE PXC Modular (BACnet)
APOGEE PXC Modular (P2 Ethernet)
TALON TC Compact (BACnet)
TALON TC Modular (BACnet)

Install updates from vendor's website.

Nucleus ReadyStart - addressed in versions 4.1.1, 2017.02.4

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

• Multiple vulnerabilities in Siemens Nucleus RTOS TCP/IP Stack
• Multiple vulnerabilities in Siemens APOGEE and TALON Products