https://www.bleepingcomputer.com/news/security/cisa-hackers-abuse-f5-big-ip-cookies-to-map-internal-servers/

CISA is warning that threat actors have been observed abusing unencrypted persistent F5 BIG-IP cookies to identify and target other internal devices on the targeted network.

By mapping out internal devices, threat actors can potentially identify vulnerable devices on the network as part of the planning stages in cyberattacks.