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ID

VDE-2021-042

Published

2021-10-18 10:24 (CEST)

Last update

2021-10-18 10:24 (CEST)

Vendor(s)

Weidmueller Interface GmbH & Co. KG

Product(s)

Article No° Product Name Affected Version(s)
1334890000 UR20-FBC-CAN <= 01.08.00
2625010000 UR20-FBC-CC <= 01.00.02
2680260000 UR20-FBC-CC-TSN <= 01.02.01
1334900000 UR20-FBC-DN <= 01.08.00
1334910000 UR20-FBC-EC <= 01.12.00
2659690000 UR20-FBC-EC-ECO <= 01.00.01
1334920000 UR20-FBC-EIP <= 02.11.00
2661310000 UR20-FBC-IEC61162-450 <= 01.01.00
2659700000 UR20-FBC-MOD-TCP-ECO <= 01.00.00
2476450000 UR20-FBC-MOD-TCP-V2 <= 02.08.01
2614380000 UR20-FBC-PB-DP-V2 <= 01.10.00
1334940000 UR20-FBC-PL <= 01.08.00
2659680000 UR20-FBC-PN-ECO <= 01.00.02
2566380000 UR20-FBC-PN-IRT-V2 <= 01.11.00

Summary

The Weidmueller Remote I/O (IP20) fieldbus couplers (u-remote) are affected by several vulnerabilities of the third-party TCP/IP Niche stack. An attacker may use crafted IP packets to cause a denial of service or breach of integrity of the affected products. Weidmueller recommends restricting network access from the internet and also locally to reduce the attack vector to a manageable minimum.

Vulnerabilities



Last Update
Sept. 7, 2021, 12:09 p.m.
Weakness
Improper Input Validation (CWE-20)
Summary

An issue was discovered in tcp_rcv() in nptcp.c in HCC embedded InterNiche 4.0.1. The TCP header processing code doesn't sanitize the value of the IP total length field (header length + data length). With a crafted IP packet, an integer overflow occurs whenever the value of the IP data length is calculated by subtracting the length of the header from the total length of the IP packet.

Last Update
Sept. 7, 2021, 12:10 p.m.
Weakness
Improper Input Validation (CWE-20)
Summary

An issue was discovered in HCC Nichestack 3.0. The code that parses TCP packets relies on an unchecked value of the IP payload size (extracted from the IP header) to compute the length of the TCP payload within the TCP checksum computation function. When the IP payload size is set to be smaller than the size of the IP header, the TCP checksum computation function may read out of bounds (a low-impact write-out-of-bounds is also possible).

Last Update
Sept. 7, 2021, 12:10 p.m.
Weakness
Improper Input Validation (CWE-20)
Summary

An issue was discovered in HCC Nichestack 3.0. The code that parses ICMP packets relies on an unchecked value of the IP payload size (extracted from the IP header) to compute the ICMP checksum. When the IP payload size is set to be smaller than the size of the IP header, the ICMP checksum computation function may read out of bounds, causing a Denial-of-Service.

Solution

Fieldbuses (including Industrial Ethernet protocols) in general are not intended for direct connection with the internet, as they lack a proper set of security capabilities. This also applies to Weidmüller IP20 Remote I/O fieldbus couplers, which are developed and designed for operation in closed industrial networks.

Remediation

  • Do not directly connect the affected products to the internet.
  • Restrict network access to the affected products by proper secured network infrastructure (e.g. routers, firewalls, DMZ, VPNs).
  • Restrict physical access to the industrial network and affected products (e.g cabinets, seals, closures).

Reported by

These vulnerabilities were discovered and reported by Forescout Technologies, Inc.
Weidmüller thanks CERT@VDE for the coordination and support with this publication.