Code RoomDNS exfiltration covert channel detected
HardPrep Room Coding #2519

DNS exfiltration covert channel detected

On-callNetworking & APIsSenior–Staff~45 min

Your network-monitoring dashboard shows one internal app server generating an unusually high volume of DNS queries — 8,000/min, up from ~50/min baseline — almost all TXT and long-label A-record lookups to subdomains of a single odd-looking domain (e.g., a1b2c3d4.exfil-cdn[.]xyz). Outbound HTTP/HTTPS egress from that host looks normal and low. The host runs a payments microservice. A dependency was updated in last week's deploy. Conventional DLP (which watches HTTP) saw nothing. How do you triage, contain, and remediate this suspected covert channel?

What a strong answer looks like

Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.

0:00 of about 45 min
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