BillyBoss
Introduction
The penetration test report contains all efforts that were conducted during client engagement. The purpose of this report is to ensure that the client has a full understanding of penetration testing methodologies as well as the technical knowlegde to remediate any security flaws.
Objective
The objective of this assessment is to perform an internal penetration test against the network. The student is tasked with following methodical approach in obtaining full control of the network. This test should simulate an attacker and how an attacker would start from beginning to end.
Requirements
The pentester will be required to fill out this penetration testing report fully and to include the following sections:
Overall High-Level Summary and Recommendations (non-technical)
Methodology walkthrough and detailed outline of steps taken
Each finding with included screenshots, walkthrough, sample code, and proof.txt if applicable
Any additional items that were not included
High-Level Summary
I was tasked with performing an internal penetration test towards the client network. An internal penetration test is a dedicated attack against internally connected systems. The focus of this test is to perform attacks, similar to those of a hacker and attempt to infiltrate internal systems. My overall objective was to evaluate the network, identify systems, and exploit flaws while reporting the findings back to the client.
When performing the internal penetration test, there were several alarming vulnerabilities that were identified on client's network. When performing the attacks, I was able to gain access to multiple machines, primarily due to outdated patches and poor security configurations. During the testing, I had administrative level access to multiple systems. All systems were successfully exploited and access granted. These systems as well as a brief description on how access was obtained are listed below:
192.168.192.61 (hostname) - Name of initial exploit
Recommendations
I recommend patching the vulnerabilities identified during the testing to ensure that an attacker cannot exploit these systems in the future. One thing to remember is that these systems require frequent patching and once patched, should remain on a regular patch program to protect additional vulnerabilities that are discovered at a later date.
Methodologies
I utilized a widely adopted approach to performing penetration testing that is effective in testing how well the environments is secured. Below is a breakout of how I was able to identify and exploit the variety of systems and includes all individual vulnerabilities found.
Information Gathering
The information gathering portion of a penetration test focuses on identifying the scope of the penetration test. During this penetration test, I was tasked with exploiting the client network. The specific IP addresses were:
Network
192.168.192.0/24
Service Enumeration
The service enumeration portion of a penetration test focuses on gathering information about what services are alive on a system or systems. This is valuable for an attacker as it provides detailed information on potential attack vectors into a system. Understanding what applications are running on the system gives an attacker needed information before performing the actual penetration test. In some cases, some ports may not be listed.
Penetration
The penetration testing portions of the assessment focus heavily on gaining access to a variety of systems. During this penetration test, I was able to successfully gain access to all systems.
System IP: 192.168.192.61
192.168.192.61
TCP: 21,80,135,139,445,5040,8081,49664-49669
UDP:
Nmap Scan Results
Foothold
Vulnerability - CVE-2020-10199
Vulnerability Explanation
Nexus Repository Manager 3 versions 3.21.1 and below are vulnerable to Java EL injection which allows a low privilege user to remotely execute code on the target server.
Vulnerability Fix
Update to the latest software release.
Severity: Critical
Reproduction Steps
With the Nmap scan I can see that there a few web ports. Beginning with port 8081 shows me a Nexus Repository Manager and a version number.
I begin to try easily guessable credentials and eventually was successful with nexus:nexus
I proceed to look for known vulnerabilities an exploits on the web application and find that this may be vulnerable to Java EL injection. I begin to download the exploit to my attacking machine.
Viewing the exploit it appears all that I need to modify is the url, command, username, and password. For fully modified exploit see Appendix B - Foothold Exploit Code
After setting up a listener, web server to supply the netcat tool, and running the exploit gives me initial access to the system
Local.txt Screenshot
Local.txt Contents
Privilege Escalation
Vulnerability -
Vulnerability Explanation
Vulnerability Fix
Severity: Critical
Reproduction Steps
Proof.txt Screenshot
Proof.txt Contents
Maintaining Access
Maintaining access to a system is important to us as attackers, ensuring that we can get back into a system after it has been exploited is invaluable. The maintaining access phase of the penetration test focuses on ensuring that once the focused attack has occurred (i.e. a buffer overflow), we have administrative access over the system again. Many exploits may only be exploitable once and we may never be able to get back into a system after we have already performed the exploit.
House Cleaning
The house cleaning portions of the assessment ensures that remnants of the penetration test are removed. Often fragments of tools or user accounts are left on an organization's computer which can cause security issues down the road. Ensuring that we are meticulous and no remnants of our penetration test are left over is important.
After collecting data from the network was completed, I removed all user accounts and passwords as well as the Meterpreter services installed on the system. the client should not have to remove any user accounts or services from the system.
Additional Items
Appendix A - Flag Contents
x.x.x.x
hash_here
hash_here
Appendix B - Foothold Exploit Code
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