In today’s rapidly evolving cybersecurity landscape, offensive and defensive tactics must advance in tandem. Pentest Copilot is an agentic AI solution for offensive security that leverages LLMNR and NTLM Relay vulnerabilities to achieve Remote Code Execution (RCE) on remote hosts.
Modern networks are full of conveniences that sometimes lead to overlooked vulnerabilities. Among these are the protocols and authentication methods designed to streamline connectivity but that also offer an attack surface for malicious actors. Pentest Copilot automates the exploitation of these vulnerabilities, combining LLMNR spoofing and NTLM Relay to ultimately grant attackers the ability to execute arbitrary code remotely. In this post, we break down every term and component involved, providing clarity on both the mechanics of the exploit and the broader implications for network security.
What It Is:
LLMNR is a protocol that enables computers on a local network to resolve names into IP addresses when traditional DNS resolution is unavailable. It is particularly useful in small or ad-hoc networks where DNS infrastructure is absent or unreliable.
How It Works:
What It Is:
NTLM is a suite of Microsoft security protocols designed to provide authentication, integrity, and confidentiality in Windows environments. It has been a cornerstone in many corporate networks despite its age and known weaknesses.
Key Characteristics:
What It Is:
NTLM Relay is a type of attack where an attacker intercepts legitimate NTLM authentication exchanges and then relays those credentials to another target system or service. This enables the attacker to impersonate the user on different network services.
How It Works:
What It Is:
Remote Code Execution (RCE) is an exploit that allows an attacker to run arbitrary code on a target machine. Achieving RCE is often the ultimate goal in many cyberattacks because it grants the attacker near-complete control over the compromised system.
Why It Matters:
Pentest Copilot streamlines the multi-stage attack process by automating several key steps:
Network Reconnaissance:
The tool begins by scanning the network, identifying active hosts and connected agents. This "infrastructure snapshot" helps define the landscape for the subsequent attack.
LLMNR Spoofing:
Upon detecting LLMNR queries on the network, the tool responds with spoofed information, effectively tricking the target into connecting to an attacker-controlled host.
Capturing NTLM Authentication:
When the target responds to the spoofed LLMNR query, its NTLM authentication challenge-response is intercepted. These captured credentials are the linchpin for the relay attack.
NTLM Relay for Exploitation:
The intercepted NTLM credentials are then relayed to a target service that accepts NTLM authentication. By doing so, the attacker can authenticate as the target user on another system within the network.
Remote Code Execution:
With valid credentials relayed to the target system, Pentest Copilot triggers a payload that executes arbitrary code on the remote host. This marks the final stage of the attack, granting the attacker control over the system.
Attack Path Visualization:
Every step of the attack—from reconnaissance to exploitation—is documented within an exploit graph. This visual mapping helps both attackers and defenders understand the full scope and sequence of the exploit.
Understanding these terms is critical for both offensive and defensive security. Here are some recommended measures to mitigate these vulnerabilities:
Disable LLMNR:
If LLMNR is not required in your network, disable it. This simple step removes a key vector for spoofing attacks.
Enforce SMB Signing:
Implement SMB signing to ensure that communications between devices are authenticated and not tampered with.
Network Segmentation:
Limit lateral movement by segmenting your network, isolating critical systems from general network traffic.
Monitor NTLM Traffic:
Use network monitoring solutions to detect abnormal NTLM authentication patterns, which may indicate ongoing relay attacks.
Adopt Modern Authentication Protocols:
Where possible, migrate to more secure protocols such as Kerberos, which offer stronger resistance to relay-based attacks.
It is essential to approach these techniques responsibly:
Obtain Explicit Authorization:
Always secure proper permissions before testing network systems. Unauthorized testing can lead to legal repercussions and damage your professional reputation.
Document Thoroughly:
Keep detailed records of your testing methodologies, findings, and remediation suggestions. This transparency is crucial for responsible disclosure and security improvement.
Share Responsibly:
When vulnerabilities are discovered, inform the appropriate stakeholders and collaborate on solutions. Your expertise can be a catalyst for improving overall network security.
Pentest Copilot represents a significant advancement in the automation of offensive security tactics. By merging LLMNR spoofing with NTLM relay, the tool not only simplifies the exploitation process but also provides a stark reminder of the vulnerabilities inherent in legacy protocols. Understanding every component—from the intricacies of LLMNR and NTLM to the devastating potential of Remote Code Execution—is vital for both attackers and defenders.
As automation reshapes the cybersecurity landscape, staying informed and vigilant is more important than ever. For more insights and updates on cutting-edge security techniques, subscribe to our newsletter and follow our ongoing research.
Happy testing, and stay secure!