GCIH Understanding Passwords Practice Question
An incident responder notices that a legacy web application stores user credentials using MD5 hashing without salt. Which vulnerability is the primary risk during a credential database compromise?
⚠ Common exam trap
Candidates often focus on the 'MD5' aspect and assume the answer is 'collision attacks'. While MD5 is weak, the specific risk of unsalted hashes in a database is precomputed rainbow table attacks.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Precomputed rainbow table attacks
MD5 is cryptographically broken and prone to collision attacks. Without a salt, identical passwords generate identical hashes, enabling precomputed rainbow table attacks. This allows attackers to instantly crack most of the database by comparing hashes against known lists. Incident responders must prioritize salting and moving to modern algorithms like Argon2 or bcrypt to ensure that stolen credentials cannot be easily reversed, protecting users from credential stuffing attacks elsewhere.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Buffer overflow in the authentication module
Why it's wrong here
Buffer overflows occur due to improper memory handling in compiled code, not hashing algorithms. While a vulnerability, it does not relate to the mathematical weakness of MD5 hashing. The issue with MD5 is the lack of salt and computational speed, not memory corruption or execution control flaws.
- ✗
SQL injection via the login form
Why it's wrong here
SQL injection is a code-level vulnerability involving improper input sanitization. While it could be used to extract the hash database, the hashing algorithm itself is independent of the vector used to steal the data. Hashing issues relate to password security, not the database query structure.
- ✓
Precomputed rainbow table attacks
Why this is correct
Rainbow tables rely on precomputed hash values for common passwords. Because MD5 is fast and unsalted, attackers can pre-calculate hashes for millions of strings. When a database is stolen, they compare the stolen hashes against the table, revealing plaintext passwords in seconds rather than days of brute forcing.
- ✗
Man-in-the-middle interception
Why it's wrong here
Man-in-the-middle attacks focus on intercepting data in transit, usually requiring the absence of TLS. Hashing issues are a storage concern rather than a network transport vulnerability. Even if traffic is encrypted, the database remains vulnerable to offline cracking if the underlying hashing algorithm is mathematically weak.
About these practice questions
This GCIH question is part of Courseiva's 322-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official GIAC exam blueprint
This GCIH practice question is part of Courseiva's free GIAC certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the GCIH exam.