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Cybersecurity remains a very important topic and point of concern for many CIOs, CISOs, and their customers. To meet these important concerns, AWS has developed a primary set of services customers should use to aid in protecting their accounts. Amazon GuardDuty, AWS Security Hub, AWS Config, and AWS Well-Architected reviews help customers maintain a strong security posture over their AWS accounts. As more organizations deploy to the cloud, especially if they are doing so quickly, and they have not yet implemented the recommended AWS Services, there may be a need to conduct a rapid security assessment of the cloud environment.
With that in mind, we have worked to develop an inexpensive, easy to deploy, secure, and fast solution to provide our customers two (2) security assessment reports. These security assessments are from the open source projects “Prowler” and “ScoutSuite.” Each of these projects conduct an assessment based on AWS best practices and can help quickly identify any potential risk areas in a customer’s deployed environment. If you are interested in conducting these assessments on a continuous basis, AWS recommends enabling Security Hub’s Foundational Security Best P ractices standard. If you are interested in integrating your Prowler assessment results with Security Hub, you can also do that from Prowler natively following instructions here.
In addition, we have developed custom modules that speak to customer concerns around threats and misconfigurations of those issues, currently this includes checks for ransomware specific findings.
The architecture we deploy is a very simple VPC with two (2) subnets, one (1) NAT Gateway, one (1) EC2 instance, and one (1) S3 Bucket. The EC2 instance is using Amazon Linux 2 (the latest published AMI), that is patched on boot, pulls down the two projects (Prowler and ScoutSuite), runs the assessments and then delivers the reports to the S3 Bucket. The EC2 instances does not deploy with any EC2 Key Pair, does not have any open ingress rules on its Security Group, and is placed in the Private Subnet so it does not have direct internet access. After completion of the assessment and the delivery of the reports the system can be terminated.
The deployment is accomplished through the use of CloudFormation. A single CloudFormation template is used to launch a few other templates (in a modular approach). No parameters (user input) is required and the automated build out of the environment will take on average less than 10 minutes to complete. These templates are provided for review in this Github repository.
Once the EC2 Instance has been created and begins, the two assessments it will take somewhere around 40 minutes to complete. At the end of the assessments and after the two reports are delivered to the S3 Bucket the Instance will automatically shutdown, You may at this time safely terminate the Instance.
Here is a diagram of the architecture.
A VPC
An EIP
A NAT Gateway
A Security Group
A single m5a.large instance with a 10 GB gp2 EBS volume
An Instance Role
An IAM Policy
An S3 Bucket
These security assessments are from the open source projects “Prowler” and “ScoutSuite.” Each of these projects conduct an assessment based on AWS best practices and can help quickly identify any potential risk areas in a customer’s deployed environment.
The first assessment is from Prowler.
The second assessment is from ScoutSuite
When enabled, this module will deploy a lambda function that checks for common security mistakes highlighted in https://www.youtube.com/watch?v=tmuClE3nWlk.
A Lambda function that will perform the checks. Some of the checks include:
When enabled, this module will deploy separate functions that can help customers with evaluating their environment for ransomware infection and susceptibility to ransomware damage.
When enabled, this module will deploy separate functions that can help customers with evaluating their environment for SolarWinds vulnerability. The checks are based on CISA Alert AA20-352A from Appendix A & B.
Note: Prior to enablement of this module, please read the module documentation which reviews the steps that need to be completed prior to using this module.
Note: This module MUST be run separately as its own stack, select the S3 URL SelfServiceSecSolar.yml to deploy
See CONTRIBUTING for more information.
This project is licensed under the Apache-2.0 License.
PowerHuntShares is design to automatically inventory, analyze, and report excessive privilege assigned to SMB shares on Active Directory domain joined computers.
It is intented to help IAM and other blue teams gain a better understand of their SMB Share attack surface and provides data insights to help naturally group related share to help stream line remediation efforts at scale.
It supports functionality to:
Excessive SMB share ACLs are a systemic problem and an attack surface that all organizations struggle with. The goal of this project is to provide a proof concept that will work towards building a better share collection and data insight engine that can help inform and priorititize remediation efforts.
Bonus Features:
I've also put together a short presentation outlining some of the common misconfigurations and strategies for prioritizing remediation here: https://www.slideshare.net/nullbind/into-the-abyss-evaluating-active-directory-smb-shares-on-scale-secure360-251762721
PowerHuntShares will inventory SMB share ACLs configured with "excessive privileges" and highlight "high risk" ACLs. Below is how those are defined in this context.
Excessive Privileges
Excessive read and write share permissions have been defined as any network share ACL containing an explicit ACE (Access Control Entry) for the "Everyone", "Authenticated Users", "BUILTIN\Users", "Domain Users", or "Domain Computers" groups. All provide domain users access to the affected shares due to privilege inheritance issues. Note there is a parameter that allow operators to add their own target groups.
Below is some additional background:
Please Note: Share permissions can be overruled by NTFS permissions. Also, be aware that testing excluded share names containing the following keywords:
FreshRSS 
print$, prnproc$, printer, netlogon,and sysvolHigh Risk Shares
In the context of this report, high risk shares have been defined as shares that provide unauthorized remote access to a system or application. By default, that includes the shares
wwwroot, inetpub, c$, and admin$ Below is a list of commands that can be used to load PowerHuntShares into your current PowerShell session. Please note that one of these will have to be run each time you run PowerShell is run. It is not persistent.
# Bypass execution policy restrictions
Set-ExecutionPolicy -Scope Process Bypass
# Import module that exists in the current directory
Import-Module .\PowerHuntShares.psm1
or
# Reduce SSL operating level to support connection to github
[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}
[Net.ServicePointManager]::SecurityProtocol =[Net.SecurityProtocolType]::Tls12
# Download and load PowerHuntShares.psm1 into memory
IEX(New-Object System.Net.WebClient).DownloadString("https://raw.githubusercontent.com/NetSPI/PowerHuntShares/main/PowerHuntShares.psm1")
Important Note: All commands should be run as an unprivileged domain user.
.EXAMPLE 1: Run from a domain computer. Performs Active Directory computer discovery by default.
PS C:\temp\test> Invoke-HuntSMBShares -Threads 100 -OutputDirectory c:\temp\test
.EXAMPLE 2: Run from a domain computer with alternative domain credentials. Performs Active Directory computer discovery by default.
PS C:\temp\test> Invoke-HuntSMBShares -Threads 100 -OutputDirectory c:\temp\test -Credentials domain\user
.EXAMPLE 3: Run from a domain computer as current user. Target hosts in a file. One per line.
PS C:\temp\test> Invoke-HuntSMBShares -Threads 100 -OutputDirectory c:\temp\test -HostList c:\temp\hosts.txt
.EXAMPLE 4: Run from a non-domain computer with credential. Performs Active Directory computer discovery by default.
C:\temp\test> runas /netonly /user:domain\user PowerShell.exe
PS C:\temp\test> Import-Module Invoke-HuntSMBShares.ps1
PS C:\temp\test> Invoke-HuntSMBShares -Threads 100 -Run SpaceTimeOut 10 -OutputDirectory c:\folder\ -DomainController 10.1.1.1 -Credential domain\user
===============================================================
PowerHuntShares
===============================================================
This function automates the following tasks:
o Determine current computer's domain
o Enumerate domain computers
o Filter for computers that respond to ping reqeusts
o Filter for computers that have TCP 445 open and accessible
o Enumerate SMB shares
o Enumerate SMB share permissions
o Identify shares with potentially excessive privielges
o Identify shares that provide reads & write access
o Identify shares thare are high risk
o Identify common share owners, names, & directory listings
o Generate creation, last written, & last accessed timelines
o Generate html summary report and detailed csv files
Note: This can take hours to run in large environments.
---------------------------------------------------------------
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---------------------------------------------------------------
SHARE DISCOVERY
---------------------------------------------------------------
[*][03/01/2021 09:35] Scan Start
[*][03/01/2021 09:35] Output Directory: c:\temp\smbshares\SmbShareHunt-03012021093504
[*][03/01/2021 09:35] Successful connection to domain controller: dc1.demo.local
[*][03/01/2021 09:35] Performing LDAP query for computers associated with the demo.local domain
[*][03/01/2021 09:35] - 245 computers found
[*][03/01/2021 09:35] Pinging 245 computers
[*][03/01/2021 09:35] - 55 computers responded to ping requests.
[*][03/01/2021 09:35] Checking if TCP Port 445 is open on 55 computers
[*][03/01/2021 09:36] - 49 computers have TCP port 445 open.
[*][03/01/2021 09:36] Getting a list of SMB shares from 49 computers
[*][03/01/2021 09:36] - 217 SMB shares were found.
[*][03/01/2021 09:36] Getting share permissions from 217 SMB shares
[*][03/01/2021 09:37] - 374 share permissions were enumerated.
[*][03/01/2021 09:37] Getting directory listings from 33 SMB shares
[*][03/01/2021 09:37] - Targeting up to 3 nested directory levels
[*][03/01/2021 09:37] - 563 files and folders were enumerated.
[*][03/01/2021 09:37] Identifying potentially excessive share permissions
[*][03/01/2021 09:37] - 33 potentially excessive privileges were found across 12 systems..
[*][03/01/2021 09:37] Scan Complete
---------------------------------------------------------------
SHARE ANALYSIS
---------------------------------------------------------------
[*][03/01/2021 09:37] Analysis Start
[*][03/01/2021 09:37] - 14 shares can be read across 12 systems.
[*][03/01/2021 09:37] - 1 shares can be written to across 1 systems.
[*][03/01/2021 09:37] - 46 shares are considered non-default across 32 systems.
[*][03/01/2021 09:37] - 0 shares are considered high risk across 0 systems
[*][03/01/2021 09:37] - Identified top 5 owners of excessive shares.
[*][03/01/2021 09:37] - Identified top 5 share groups.
[*][03/01/2021 09:37] - Identified top 5 share names.
[*][03/01/2021 09:37] - Identified shares created in last 90 days.
[*][03/01/2021 09:37] - Identified shares accessed in last 90 days.
[*][03/01/2021 09:37] - Identified shares modified in last 90 days.
[*][03/01/2021 09:37] Analysis Complete
---------------------------------------------------------------
SHARE REPORT SUMMARY
---------------------------------------------------------------
[*][03/01/2021 09:37] Domain: demo.local
[*][03/01/2021 09:37] Start time: 03/01/2021 09:35:04
[*][03/01/2021 09:37] End time: 03/01/2021 09:37:27
[*][03/01/2021 09:37] R un time: 00:02:23.2759086
[*][03/01/2021 09:37]
[*][03/01/2021 09:37] COMPUTER SUMMARY
[*][03/01/2021 09:37] - 245 domain computers found.
[*][03/01/2021 09:37] - 55 (22.45%) domain computers responded to ping.
[*][03/01/2021 09:37] - 49 (20.00%) domain computers had TCP port 445 accessible.
[*][03/01/2021 09:37] - 32 (13.06%) domain computers had shares that were non-default.
[*][03/01/2021 09:37] - 12 (4.90%) domain computers had shares with potentially excessive privileges.
[*][03/01/2021 09:37] - 12 (4.90%) domain computers had shares that allowed READ access.
[*][03/01/2021 09:37] - 1 (0.41%) domain computers had shares that allowed WRITE access.
[*][03/01/2021 09:37] - 0 (0.00%) domain computers had shares that are HIGH RISK.
[*][03/01/2021 09:37]
[*][03/01/2021 09:37] SHARE SUMMARY
[*][03/01/2021 09:37] - 217 shares were found. We expect a minimum of 98 shares
[*][03/01/2021 09:37] because 49 systems had open ports a nd there are typically two default shares.
[*][03/01/2021 09:37] - 46 (21.20%) shares across 32 systems were non-default.
[*][03/01/2021 09:37] - 14 (6.45%) shares across 12 systems are configured with 33 potentially excessive ACLs.
[*][03/01/2021 09:37] - 14 (6.45%) shares across 12 systems allowed READ access.
[*][03/01/2021 09:37] - 1 (0.46%) shares across 1 systems allowed WRITE access.
[*][03/01/2021 09:37] - 0 (0.00%) shares across 0 systems are considered HIGH RISK.
[*][03/01/2021 09:37]
[*][03/01/2021 09:37] SHARE ACL SUMMARY
[*][03/01/2021 09:37] - 374 ACLs were found.
[*][03/01/2021 09:37] - 374 (100.00%) ACLs were associated with non-default shares.
[*][03/01/2021 09:37] - 33 (8.82%) ACLs were found to be potentially excessive.
[*][03/01/2021 09:37] - 32 (8.56%) ACLs were found that allowed READ access.
[*][03/01/2021 09:37] - 1 (0.27%) ACLs were found that allowed WRITE access.
[*][03/01/2021 09:37] - 0 (0.00%) ACLs we re found that are associated with HIGH RISK share names.
[*][03/01/2021 09:37]
[*][03/01/2021 09:37] - The 5 most common share names are:
[*][03/01/2021 09:37] - 9 of 14 (64.29%) discovered shares are associated with the top 5 share names.
[*][03/01/2021 09:37] - 4 backup
[*][03/01/2021 09:37] - 2 ssms
[*][03/01/2021 09:37] - 1 test2
[*][03/01/2021 09:37] - 1 test1
[*][03/01/2021 09:37] - 1 users
[*] -----------------------------------------------
Author
Scott Sutherland (@_nullbind)
Open-Source Code Used
These individuals wrote open source code that was used as part of this project. A big thank you goes out them and their work!
| Name | Site |
|---|---|
| Will Schroeder (@harmj0y) | https://github.com/PowerShellMafia/PowerSploit/blob/master/Recon/PowerView.ps1 |
| Warren F (@pscookiemonster) | https://github.com/RamblingCookieMonster/Invoke-Parallel |
| Luben Kirov | http://www.gi-architects.co.uk/2016/02/powershell-check-if-ip-or-subnet-matchesfits/ |
License
BSD 3-Clause
Pending Fixes/Bugs
Pending Features
