Offensive Network Security Techniques
Scanning
Active network scanning techniques allow attackers to actively engage with the network to identify hosts, open ports, and available services. Tools like nmap and masscan are commonly used. This process involves sending packets to hosts and analyzing the responses to map the network's structure. Stealth scanning techniques, such as SYN scanning, help avoid detection by IDS/IPS systems.
Example command to identify live hosts and open ports:
nmap -sS -p 1-65535 -T4 <target>
Passive reconnaissance involves capturing and scrutinizing network traffic without directly interacting with hosts. This can be performed using tools like Wireshark, which helps uncover the network's topology and identify devices based on traffic patterns. Capturing traffic on a network port allows analysts to dissect and understand network communications without being detected.
Visualizing the network topology helps attackers plan their attack path by identifying key devices and communication paths. Tools like Maltego can be utilized to create a visual map of the network.
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Enumeration
Service enumeration is a crucial step for gaining detailed intel about the services running on discovered hosts. By fingerprinting services on open ports, attackers can gather software versions and configurations to identify potential vulnerabilities.
Protocol-specific enumeration, such as [SMB](offensive/network/SMB\ Enumeration), [LDAP](offensive/network/LDAP\ Enumeration), and [SNMP](offensive/network/SNMP\ Enumeration) enumeration, involves gathering detailed information about network services and devices. Tools like enum4linux can extract valuable insights into the network's structure, users, and services.
User and group enumeration aims to identify valid user accounts and group memberships within a network. This information can be leveraged for brute force attacks or to gain unauthorized access to shared resources. Techniques vary based on the targeted protocols and systems.
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Initial Access Techniques
Credential harvesting involves capturing login details through MITM attacks or exploiting weak service configurations. Attackers may set up rogue access points or phishing campaigns to trick users into revealing credentials.
Phishing for network access can involve crafting specialized emails to lure victims into disclosing credentials or clicking malicious links. Using compromised accounts or exploiting wrongly configured network elements, attackers can achieve initial access.
Exploiting vulnerabilities in network services is a common avenue for initial access. Tools like Metasploit automate the exploitation process, enabling attackers to exploit vulnerabilities in services like [HTTP](offensive/network/HTTP\ Exploitation) or [SMB](offensive/network/SMB\ Exploitation).
Explore more about [initial access techniques](offensive/network/Initial\ Access\ Techniques).
Exploitation
Exploit development for network services involves crafting custom code to trigger and exploit identified vulnerabilities. Attackers analyze the service’s code to inject payloads, allowing them to gain control of the service or underlying system.
Weaponizing protocols involves exploiting inherent weaknesses or misconfigurations in protocols like [RDP](offensive/network/RDP\ Exploitation) or [FTP](offensive/network/FTP\ Exploitation) to perform unauthorized actions. This could be achieved using techniques like protocol fuzzing or exploiting authentication weaknesses.
Automated exploit tools such as Metasploit or Canvas streamline the process of delivering exploits against known vulnerabilities, significantly simplifying attackers' tasks. These tools often include a range of exploits targeted at various services and systems.
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Post Exploitation
Network pivoting techniques allow attackers to use a compromised host as a launch point for further attacks within the network. This is often done by setting up tunnels through compromised systems to access additional network resources.
Data exfiltration involves extracting sensitive information from a network in a stealthy manner. Attackers often compress and encrypt data before exfiltration to avoid detection, utilizing secure channels that blend in with normal traffic patterns.
Traffic redirection uses methods such as ARP poisoning or DNS spoofing, allowing attackers to reroute legitimate traffic through malicious nodes for data capture or manipulation.
Learn about more [post-exploitation methods](offensive/network/Post\ Exploitation).
Privilege Escalation
Local privilege escalation exploits known vulnerabilities or misconfigurations to gain higher privilege levels on networked systems. Techniques include exploiting kernel vulnerabilities or abusing poorly set sudo policies.
Network misconfigurations provide avenues for escalating privileges by exploiting weak permission settings or mismanaged access controls, often seen in things like over-permissive shares or user groups.
By abusing protocol weaknesses, attackers can authorize themselves broader access than intended, such as gaining domain admin privileges via [Kerberos](offensive/network/Kerberos\ Privilege\ Escalation) or exploiting legacy technologies with default credentials.
Expand your understanding of [privilege escalation techniques](offensive/network/Privilege\ Escalation).
Lateral Movement
Leveraging network trust relationships involves using compromised credentials or trust delegate tokens to access new areas of the network. Attackers exploit trust among systems to move laterally and escalate the impact of their campaign.
Credential relaying and reuse consist of capturing and repurposing valid credentials found in one system to access another. Techniques like Pass-the-Hash are commonly used to gain access using previously captured password hashes.
Tunneling and port forwarding set up tunnels to pass traffic through compromised systems, often obscuring attacker activities. SSH tunneling can be used to securely route commands through secure systems, evading detection.
Learn more about [lateral movement strategies](offensive/network/Lateral\ Movement).
Persistence Techniques
Establishing network backdoors allows attackers to maintain access over longer periods by implanting malicious firmware or compromised configurations in devices like routers or switches.
Using legitimate channels, attackers embed themselves within maintenance scripts or software used routinely in the network, ensuring persistent access while blending with normal operations.
Network service persistence mechanisms involve techniques like modifying critical service configurations or injecting malicious scripts into server startup services, ensuring the attacker's foothold remains intact across reboots.
Gain insights into [persistence mechanisms in network environments](offensive/network/Persistence\ Techniques).