SYNful Knock

Malware Profile Updated 3 months ago
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"SYNful Knock" is a form of malware that specifically targets Cisco devices running the Cisco IOS. First identified in 2015, it functions by installing an implant within the targeted device, creating a persistent access point that is challenging to detect. This malware represents one of seven known incidents over the past four years where Cisco IOS devices have been the focus of malicious attacks. The stealthy nature of SYNful Knock involves modifying the router's firmware image, a tactic used to maintain persistence within the victim's network. The operation of SYNful Knock is characterized by static modifications to the Cisco IOS binary, mirroring tactics seen in previous incidents. Despite its sophisticated design, SYNful Knock, like malware instances #0, #1, #2, and #3, cannot withstand the installation of a verified good Cisco IOS binary image sourced from a trusted entity. Ensuring the correct hash values can effectively neutralize the threat posed by this malware. In response to the emergence and subsequent detection of SYNful Knock, practical methods and tools for identifying a compromise have been developed and shared publicly. Notably, SNORT and Yara signatures have been released to aid in detecting the presence of this specific malware. These proactive measures aim to bolster defenses against SYNful Knock, helping to secure Cisco IOS devices from further exploitation.
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Implant
Ios
Malware
Cisco
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Source Document References
Information about the SYNful Knock Malware was read from the documents corpus below. This display is limited to 20 results, create a free account to see more
SourceCreatedAtTitle
CERT-EU
6 months ago
Infographic: A History of Network Device Threats and What Lies Ahead
CERT-EU
6 months ago
Infographic: A History of Network Device Threats and What Lies Ahead | #ransomware | #cybercrime | National Cyber Security Consulting
MITRE
a year ago
SYNful Knock - A Cisco router implant - Part I | Mandiant
MITRE
a year ago
Evolution of attacks on Cisco IOS devices