Welcome back, aspiring cyberwarriors!

Sometimes you might run the same model twice and get different results. That often happens when you’ve upgraded it with skills. Skills are detailed text documents that lay out the tools the model should use, the approach it should take and how it should analyze the results. Good skills are practical, pulled from actual reports on HackerOne and other bug bounty platforms. A model can still lean on its own knowledge, but that’s just less efficient.

There are plenty of skills out there you might come across, but not everything can be trusted. Some skills can simply be dangerous and infect your system. To make sure they are safe, you can check them with SkillSpector by NVIDIA, so you don’t end up with anything malicious on your system.

Bug Bounty Skills

Both of these repositories do bug bounty hunting end to end, but they go about it in almost opposite ways.

The first is called Bountyforge. It’s actually just one single skill file, but it’s smart enough to split itself into eight different mini agents that all work at the same time. One looks at websites and apps, another at crypto and blockchain, others go after different angles hackers can exploit. It also checks each finding with four different tests to make sure it’s not a false alarm. Then you get a report in whatever format the bug bounty program wants.

You don’t even need Claude Code or any other coding tool for this, you can just run it right inside the regular Claude website in your browser.

The second bug bounty repository is Claude-BugHunter. It takes the opposite approach. The repo has 83 skills and almost half of those were built by studying 681 real bug reports that people actually got paid for on HackerOne. These skills aren’t locked to Claude Code either, you can use OpenCode, Codex or Hermes Agents with them.

Here are a few examples of the results we got with these skills.

API endpoints are often vulnerable and this is worth trying your luck on to see how it goes.

Another approach can be APK reverse engineering. Here we found a hardcoded RSA-2048 signing private key baked into the published APK. With that key, hackers can push a new app to the app store and infect every employee phone, getting access not just to the WiFi network at the workplace but to their personal life too. Quite dangerous.

We found an API endpoint vulnerable to an SQL injection and managed to pull the entire database.

Having skills built on real attacks keeps the model from wandering off into its own weird approaches and missing a lot of good findings. 

Active Directory Skills

Claude-AD was made by ADScanPro for testing a company’s internal network. It gives your model a playbook with skills and agents built for an Active Directory assessment. The developers are upfront that it’s not an auto pwn tool. It’s meant to guide you through the assessment. Every finding can get mapped to a compliance control (DORA, NIS2 and ENS).

Claude-AD is very careful about getting caught too. It explains what a security team would actually see on their end if that technique got used. And any time it’s about to do something that would actually change things on the company’s network, it stops and asks for confirmation first.

General Cybersecurity Skills

Antropic-Cybersecurity-Skills is basically a giant reference book. It has 817 skills covering 29 areas of security work, cloud security, malware analysis, all the way down to hardware and firmware. Each skill is its own small file, so your agent will quickly pull out the two or three it actually needs for its task.

Every skill ties back to real security frameworks that companies and auditors already use (NIST CSF, MITRE ATT&CK and so on). So if your model finds a problem using one of these skills, it can also tell you exactly which official standard it violates. You can use it to justify findings to a compliance team.

SCADA Skills

On an industrial network, a clumsy scan can shut down a production line or damage physical equipment, since a lot of this gear is old and wasn’t built to handle unexpected traffic. That’s why the ICS skill by Masriyan is built to never actively touch a live industrial network. Instead, it works off network captures someone already took. It reads the file, recognizes industrial protocols by the ports they normally run on (Modbus, DNP3, Siemens S7, EtherNet/IP, OPC-UA, and more) and counts which devices are talking to each other. It then shows you write commands, these are the ones that change a value on an industrial device. That’s the traffic you want to see first.

The second mode skips network captures and instead searches for exposed industrial equipment using Shodan and Censys. The skill can also help your model reason about how an industrial network is laid out and check findings against MITRE’s ICS specific attack framework and the IEC 62443 security standard.

Science Skills

Although science isn’t really what we want to focus on here, in one of our SCADA articles we mentioned that to carry out a successful attack requires hackers to understand the technical process of the plant. That means understanding how the chemicals are produced and which units are used along the way. We also showed how vinyl acetate is produced and talked about paracetamol production.

1 kg of paracetamol at 100% purity was reported to cost €8,205, while 1 kg at 99% purity cost just €5. So even a single day of sabotage could cause serious financial damage to an enterprise.

Finding a scientist among hackers is quite a challenge, which is why Stuxnet needed a group of people from different backgrounds working toward one objective. But now hackers can just import different skills to make their attacks more devastating. K-Dense published 140 skills with access to different scientific databases and Python tools.

The real concern here isn’t ICS exploits inside the repository, there aren’t any. It’s the access to sensitive scientific data paired with an AI agent that can actually understand that data and change it.

Summary

AI skills can be a gamechanger, especially when they’re based on actual reports hackers got paid for. These skills show your model how to approach things and what tools to use during the test, so it doesn’t wander off hallucinating and inventing its own ways of testing things. That can wreck your bug bounty flow, since you’ll end up overlooking plenty of potential targets.

Simply relying on the AI to find things isn’t enough, hunters that do it keep getting a lot of dupes. You need to test things manually too. For this reason we created our Bug Bounty training to show you how to find bugs and work with the AI more efficiently.

The post Artificial Intelligence (AI) in Cybersecurity, Part 25: Upgrading Your Model with Specific Skillset first appeared on Hackers Arise.

Welcome back, pentesters!

Some of you have probably heard about Group Policies and that you need to “check the GPOs” a few times without anyone actually explaining to you why. We’re going to fix that. Group Policy has been part of Active Directory for a long time and it’s still one of the first things pentesters should check. Mainly because it’s boring and boring things are often ignored by admins.

A GPO can hold a cleartext password. It may have a script with internal paths and usernames. It can also be edited by someone who left the team and never got their permissions pulled. These things don’t require any exploit, you just need to know where to look.  

What is a GPO

A Group Policy Object is actually two things stuck together. Often beginners only learn about one of them. The first half lives in Active Directory. It’s an object with a name, an owner, a list of who can edit it and a list of where it’s linked. This is the part that Group Policy Management Console (GPMC) shows you. The second half lives on a file share called SYSVOL (e.g. \\sekvoya.local\SYSVOL\sekvoya.local\Policies\{GUID}\). This folder holds the actual settings and has registry values, XML files, scripts and more. 

Any domain user can usually read SYSVOL. So if something sensitive is dropped in there (a stored password or a script with internal server names) you can extract it. 

We’re going to use GPOZaurr for most of this. It’s a legitimate PowerShell module made for GPO audit.

Here is how you set it up:

PS > Add-WindowsCapability -Online -Name 'Rsat.ActiveDirectory.DS-LDS.Tools~~~~0.0.1.0'

PS > Add-WindowsCapability -Online -Name 'Rsat.GroupPolicy.Management.Tools~~~~0.0.1.0'

PS > Install-Module -Name GPOZaurr -AllowClobber -Force
PS > Import-Module GPOZaurr

What GPOs Exist?

Before we start hunting for anything, let’s see what GPOs exist in the domain. Later we will pull the secrets. 

PS > Get-GPOZaurr | Format-Table DisplayName, DomainName, Empty, Linked, Enabled -AutoSize

For every GPO it tells you whether it holds settings (Empty), whether anything actually links to it (Linked) and shows their status (Enabled).

As you can see, Map Network Drives – Finance is empty and not linked anywhere, someone started building a drive mapping policy and just never finished it. WSUS Settings – Old has a setting but isn’t linked to anything, so it does nothing to any computer. It just sits there. Remote Desktop – Vendors are linked but disabled. That can happen if we gave vendors RDP access at some point, then turned it off and never deleted the policy.

It’s important to understand that unlinked and disabled don’t mean safe. The object still exists. The SYSVOL folder behind it still exists. That’s where old Groups.xml files and forgotten scripts sit around waiting to be found. Stick for it. 

Where Do They Apply?

Once you know that a GPO exists, you should look up what computers it affects. Only linked GPOs can affect computers. A link basically means that this GPO applies to this domain, this site or this OU.

PS > Get-GPOZaurrLink | Format-Table DisplayName, CanonicalName, Enabled, Enforced -AutoSize

Enabled here describes the link, not the GPO itself. It means the attachment is switched on. Enforced means this GPO wins even if a lower OU tries to block it. In our table nothing is enforced. Blocked inheritance is a setting on the OU itself that prevents handing policies from above unless they’re enforced.

Everything here lands on sekvoya.local/Workstations-Temp. That OU also blocks inheritance, because these are temp machines and nobody wants the domain-wide policy fighting with their imaging process.

You’ll also see Remote Desktop – Vendors that are Enabled, even though we said earlier the GPO itself is disabled. You can absolutely have a live link pointing at a dead GPO and it’ll still show up here.

The GPO linked to Workstations-Temp means every computer in that OU applies it. Always ask “linked where”. Domain root and the Domain Controllers OU are the highest value targets.

Let’s list what computers are in Workstations-Temp.

PS > Get-ADComputer -SearchBase "OU=Workstations-Temp,DC=sekvoya,DC=local" -Filter * | Select-Object Name, DistinguishedName

Look Inside the GPOs

Now that we know which GPOs hit Workstations-Temp, we can find out what they actually do.

PS > Find-GPO -GPOName 'Local Administrator Password' -SingleObject
PS > Find-GPO -GPOName 'Logon Script - Standard User' -SingleObject
PS > Find-GPO -GPOName 'WSUS Settings - Old' -SingleObject

Find-GPO reads the GPT, which is just the SYSVOL content and prints it. But in our case, only WSUS was printed with a DNS name and a link. But “empty” doesn’t always mean empty. Get-GPOZaurr and Find-GPO mostly trust Active Directory. They look at the GPO’s version number and its extension attributes (gPCMachineExtensionNames and gPCUserExtensionNames). If a setting was pushed through GPMC properly, those fields get updated and the GPO shows up as not empty.

You might find an environment where that’s not the case. Files can be dropped straight onto SYSVOL by hand.

Listing Files

For the reason mentioned above, we won’t trust the output and list all the files ourselves. 

PS > Get-GPOZaurrFiles | Format-Table GPOName, FullName, Length -AutoSize

Here we’re not querying Active Directory, that’s why we get the output. It’s showing us the actual Policies folder tree and listing what’s inside. We can open the same folders as any domain user in Explorer.

Our SYSVOL has Groups.xml with cpassword, logon.bat and office2013.adm, which is a legacy ADM template that tells you this domain hasn’t been cleaned up since 2013. Readme.txt has some notes. Take some time and look through your output.

Decrypting the Password

Let’s take a look at Groups.xml and see its structure. 

PS > findstr /s /i cpassword \\sekvoya.local\sysvol\*.xml

Above you can see cpassword. It was introduced in Windows Server 2008 to let administrators manage domain-wide settings and deploy local administrator passwords. Microsoft encrypted the passwords using AES, but then made the private encryption key public. We can use NetExec to extract and decode the password stored there. 

kali > nxc smb DC -u user -p password 

Permission to Change 

Reading SYSVOL can give you old leftover passwords. But we can also find out who can push something new into a GPO that’s still live.

PS > Get-GPOZaurrPermission | Where-Object { $_.DisplayName -eq 'Local Admins - Workstations' } | Format-Table DisplayName, PrincipalName, Permission, PrincipalSidType -AutoSize

This pulls the ACL on the GPO object inside our AD, which tells you who can read it, who can make it apply to them, edit and change security settings. GpoRead and GpoApply mean you can see the GPO or have it apply to you, which is completely normal for Authenticated Users or Domain Computers. GpoEdit and GpoEditDeleteModifySecurity mean you can actually change settings or change who else is allowed to.

In our lab, jpatel has GpoEditDeleteModifySecurity on Local Admins – Workstations, and that GPO is linked to Workstations-Temp. Domain Users also have GpoApply on it, which is normal on the surface. Somebody got delegated edit rights on a GPO for some project or ticket (helpdesk). The ticket closed months ago, but nobody went back and pulled the permission. So not only can you read the leftover password, you can also edit rights on a linked GPO and write the next one. Those are two very different levels of access.

A low privileged user who can edit a linked GPO can add things like an Immediate Scheduled Task, a Restricted Groups entry or a startup script. These can turn into code execution on every machine that GPO touches. SharpGPOAbuse and pyGPOAbuse are built for that. GPOZaurr can only find things and fix them. The actual abuse is a separate topic.

Ownership

An edit permission is one entry on a list. Ownership is stronger, because whoever owns the Active Directory object can usually reset the entire access list from scratch. When they own the SYSVOL folder, they can change the files directly, even if the AD permissions look locked down tight. Both of those owners are supposed to be Domain Admins or BUILTIN\Administrators. But this can drift over time, especially if a company is big. 

PS > Get-GPOZaurrOwner -IncludeSysvol | Where-Object { $_.DisplayName -eq 'Printer Deployment - 3rd Floor' } | Format-Table DisplayName, Owner, OwnerType, SysvolOwner -AutoSize

In our lab, Printer Deployment – 3rd Floor is owned by jpatel. That’s the same user who could edit the local admins GPO. So we have two separate mistakes, but one person behind both of them. At some point they deployed printers on the 3rd floor and picked up more access than they should have kept.

If you compromise jpatel, you own an entire GPO object outright. Their helpdesk account can be used to write policy for a whole OU.

Summary

We tried to simplify the concept of GPOs and how they work in Active Directory. As you can see, credentials can hide not only in LDAP user description and text files on the workstation, but also on the Domain Controller itself in SYSVOL that any domain user can read. Hackers often abuse GPOs and create their own policies affecting all computers and in the domain disabling Defender and booting them into Safe Mode to execute ransomware. This abuse has been reported several times. 

There are a lot of different options for escalating your privileges in a misconfigured domain. The boring and complex things like GPOs and ADCS are often left vulnerable, simply because they are tedious to work with. But not for you!

Want to become a Powershell expert? Join our Powershell for Hackers training.

The post Pentesting: Group Policy for Hackers – Basics first appeared on Hackers Arise.