computer science

Pwdump

Pwdump is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pwdump rather than just read about it. In short: pwdump is the name of various Windows programs that outputs the LM and NTLM password hashes of local user accounts from the Security Account Manager (SAM) database and from the Active Directory domain's users cache on the operating system. It is widely used, to perform both the famous pass-the-hash attack, or also can be used to brute-force users' password directly.

Key takeaways

Pwdump belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pwdump to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pwdump from memory before moving on to harder problems.

Reference excerpt

pwdump is the name of various Windows programs that outputs the LM and NTLM password hashes of local user accounts from the Security Account Manager (SAM) database and from the Active Directory domain's users cache on the operating system. It is widely used, to perform both the famous pass-the-hash attack, or also can be used to brute-force users' password directly. In order to work, it must be run under an Administrator account, or be able to access an Administrator account on the computer where the hashes are to be dumped. Pwdump could be said to compromise security because it could allow a malicious administrator to access user's passwords.

History

The initial program called pwdump was written by Jeremy Allison. He published the source code in 1997 (see open-source). Since then there have been further developments by other programmers:

pwdump (1997) — original program by Jeremy Allison. pwdump2 (2000) — by Todd Sabin of Bindview (GPL), uses DLL injection. pwdump3 — by Phil Staubs (GPL), works over the network. pwdump3e — by Phil Staubs (GPL), sends encrypted over network. pwdump4 — by bingle (GPL), improvement on pwdump3 and pwdump2. pwdump5 — by AntonYo! (freeware). pwdump6 (c. 2006) — by fizzgig (GPL), improvement of pwdump3e. No source code. fgdump (2007) — by fizzgig, improvement of pwdump6 w/ addons. No source code. pwdump7 — by Andres Tarasco (freeware), uses own filesystem drivers. No source code. pwdump8 — by Fulvio Zanetti and Andrea Petralia, supports AES128 encrypted hashes (Windows 10 and later). No source code.

Notes

References Allison, Jeremy (30 September 2012). "Index of /pub/samba/pwdump". Samba. Retrieved 15 June 2017. Sabin, Todd (1 February 2017). "New version of PWDump2 allows dumping of password hashes Active Directory". SecuriTeam.com. Retrieved 15 June 2017. "pwdump8". forums.hak5.org. 15 May 2019.

Worked examples

Example 1 — a first encounter with Pwdump

Start with the simplest possible case. Write down what Pwdump claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pwdump before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pwdump ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pwdump

In research: Pwdump appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pwdump in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pwdump is common in secondary-school and first-year university syllabi. It links to neighbouring topics Command-line software, Computer security software stubs, Cryptographic attacks, so understanding it makes those chapters shorter.
In everyday life: Look for Pwdump outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pwdump in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pwdump means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pwdump out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pwdump in simple terms?

Why does Pwdump matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pwdump?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pwdump.