Notifications
Clear all
Topic starter
06/06/2026 11:14 am
TL;DR: Rainbow table attacks show how precomputed hash lookup can crack weak password storage, but salts and slow hashing render the technique impractical for properly designed systems, according to WorkOS. The real lesson is that password security fails when teams treat hashing as protection without building for precomputation, cost, and uniqueness.
NHIMG editorial — based on content published by WorkOS: Rainbow table attacks: What they are and how to prevent them
Questions worth separating out
Q: How should security teams prevent rainbow table attacks on password hashes?
A: Use a modern password hashing algorithm such as Argon2id or bcrypt, generate a unique random salt for every password, and tune the work factor so hashing is intentionally slow.
Q: Why do unsalted password hashes remain risky even when the hash function is strong?
A: A strong hash function does not stop precomputation if every user shares the same input pattern.
Q: What breaks when organisations use fast general-purpose hashes for password storage?
A: Fast hashes such as SHA-256 make offline guessing cheap because attackers can test huge numbers of candidates per second.
Practitioner guidance
- Inventory legacy password hashing schemes Identify every application and directory that still stores unsalted MD5, SHA-1, or similarly fast password hashes.
- Standardise on per-password unique salts Verify that every password hashing path generates a cryptographically random salt per credential and stores it with the hash.
- Move to slow, memory-hard password hashing Use Argon2id where supported, or bcrypt where platform constraints require it, and tune the work factor so a verification takes roughly 100 milliseconds on production hardware.
What's in the full article
WorkOS's full article covers the operational detail this post intentionally leaves for the source:
- Walkthrough of hashing, reduction functions, and chain construction for rainbow tables.
- Examples of how salting blocks precomputed lookup against identical passwords.
- Practical guidance on choosing Argon2id, bcrypt, or another password-specific hash in your stack.
👉 Read WorkOS's explainer on rainbow table attacks and password hashing →
Rainbow table attacks and password hashing: what teams still miss?
Explore further
06/06/2026 11:54 am
Rainbow table resistance is a password storage design problem, not an authentication feature. The article shows that the attack succeeds when teams store reusable hashes without uniqueness or cost controls. That means the security boundary sits in how passwords are transformed and stored, not in the login prompt itself. Practitioners should treat password hashing as a control surface that needs explicit governance, not a background implementation detail.
A few things that frame the scale:
- 1.5 out of 10 organisations are highly confident in their ability to secure NHIs, compared to nearly 1 in 4 for securing human identities, according to Astrix Security & CSA.
- Lack of credential rotation is cited as the top cause of NHI-related attacks by 45% of organisations, followed by inadequate monitoring and logging at 37% and over-privileged accounts at 37%.
A question worth separating out:
Q: How do teams know whether password hashing is actually strong enough?
A: Check three things: every password has a unique salt, the hash algorithm is password-specific, and the verification cost is high enough to slow attackers without harming users. If any of those is missing, the system still leaves room for efficient offline cracking.
👉 Read our full editorial: Rainbow table attacks expose why password hashing needs salts
