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NASA·Software Engineer·Technical Phone Screen·Senior

Senior
May 2026

Summary

Interviewed for a security engineer role at NASA, got asked about Kerberos attack techniques. Pretty niche stuff for a government gig but I guess it makes sense given the threat landscape they deal with.

Questions Asked (1)

Q1

Can you explain what a golden ticket attack is?

Technical Trade-offsSystem Design
Author's notes

Knew this one cold.

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AI HintsAI Generated

Suggested Approach

Define a golden ticket attack as a Kerberos exploitation technique where an attacker forges a Ticket Granting Ticket (TGT) using the KRBTGT account hash, granting unrestricted access. Explain the attack flow, its prerequisites, and its impact on Active Directory environments, then discuss mitigation strategies relevant to a high-security context like NASA.

Pro tip: Emphasize that detecting golden ticket attacks is extremely difficult because forged TGTs have a default lifetime of 10 years and can be created offline; thus, prevention (protecting the KRBTGT hash) and monitoring for anomalous TGT usage are critical.

1. Define the attack

State that a golden ticket attack involves forging a Kerberos TGT using the KRBTGT account's NTLM hash, allowing the attacker to impersonate any user in the domain.

2. Explain the mechanics

Describe how the attacker obtains the KRBTGT hash (e.g., via DCSync or compromising a domain controller), then uses it to create a TGT with arbitrary privileges and a long lifetime.

3. Discuss impact and detection

Highlight that the forged TGT grants domain admin access, persists even after password changes (unless KRBTGT is reset twice), and is hard to detect because it appears legitimate.

4. Cover mitigation strategies

Mention protecting the KRBTGT account, regularly rotating its password twice, monitoring for anomalous TGT lifetimes or encryption types, and implementing tiered administration.

5. Relate to system design

Connect to broader system design principles: defense in depth, least privilege, and the importance of securing identity infrastructure in large-scale environments like NASA's.

Key Points to Mention

  • Kerberos authentication protocol and the role of TGTs
  • KRBTGT account and its NTLM hash as the key to forging tickets
  • DCSync attack or domain controller compromise as common precursors
  • Unrestricted access and persistence (default 10-year ticket lifetime)
  • Detection challenges: forged tickets blend with legitimate traffic
  • Mitigation: KRBTGT password rotation (twice), monitoring, and privileged access workstations

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.