Cisco Bug: CSCvu63661 - Umbrella: DNS resolution hangs globally after sending multiple TCP DNS requests with large response
Aug 17, 2020
- Cisco AnyConnect Secure Mobility Client
Known Affected Releases
Symptom: DNS resolution stops working (hangs) regardless of DNS query or app issuing it. Conditions: - Platform: maCOS, Windows - AnyConnect Umbrella DNS protection active. - Send multiple TCP DNS requests that produce a large (>512 bytes) response, e.g. via command for /l %i in (1,1,400) do nslookup -type=txt -vc t4096.frag.Awfulhak.org on Windows. - Note that it may take a few hundred requests to reproduce.
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Bug Details Include
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