Description
A predictable value range from previous values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections.
Problem types
Product status
Any version before 1.5.0.0
Any version before 4.0.5.11
Any version before 4.0.5.11
Credits
David Formby and Raheem Beyah of Georgia Tech and Fortiphyd Logic, Inc. reported the identified vulnerabilities.
References
ics-cert.us-cert.gov/advisories/ICSA-17-089-02
www.securityfocus.com/bid/97254 (97254)
ics-cert.us-cert.gov/advisories/ICSA-17-089-02
www.securityfocus.com/bid/97254 (97254)
github.com/...p/csaf_files/OT/white/2017/icsa-17-089-02.json