Home/ATT&CK Technique/Adversary-in-the-Middle
ATT&CK Technique

Adversary-in-the-Middle

T1557 · credential-access, collection

Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as Network Sniffing, Transmitted Data Manipulation, or replay attacks (Exploitation for Credential Access). By abusing features of common networking protocols that can determine the flow of network traffic (e.g. ARP, DNS, LLMNR, etc.), adversaries may force a device to communicate through an adversary controlled system so they can collect information or perform additional actions.

For example, adversaries may manipulate victim DNS settings to enable other malicious activities such as preventing/redirecting users from accessing legitimate sites and/or pushing additional malware. Adversaries may also manipulate DNS and leverage their position in order to intercept user credentials, including access tokens (Steal Application Access Token) and session cookies (Steal Web Session Cookie). Downgrade Attacks can also be used to establish an AiTM position, such as by negotiating a less secure, deprecated, or weaker version of communication protocol (SSL/TLS) or encryption algorithm.

Adversaries may also leverage the AiTM position to attempt to monitor and/or modify traffic, such as in Transmitted Data Manipulation. Adversaries can setup a position similar to AiTM to prevent traffic from flowing to the appropriate destination, potentially to impair defenses and/or in support of a Network Denial of Service.

LinuxmacOSNetwork DevicesWindows

Actors Using This

14
russiaAPT28
iranOilRig
iranAPT35
brazilBanbra
israel_commercial_cyber_mercenaryCandiru / Sourgum
south_koreaDarkhotel
uae_commercial_cyber_mercenaryDarkMatter / Project Raven
us_israel_joint_offensive_cyber_speculationFlame
multinational_commercial_cyber_mercenaryIntellexa / Predator / Cytrox
north_koreaLazarus Group
israel_commercial_cyber_mercenaryNSO Group / Pegasus
unattributed_apt_nation_state_speculationOperation Triangulation
israel_commercial_cyber_mercenaryParagon Solutions / Graphite

Likely Attack Path

Techniques the same actors pair with this one distinctively - those showing up among actors who use this technique noticeably more than across all actors (lift > 1.15), grouped by kill-chain phase. The × is that lift multiplier; the shared-actor count is in the tooltip. A near-universal technique pairs with everything at baseline, so its list is short by design.
resource-development earlier
initial-access earlier

Mitigations

7
MITRE ATT&CK mitigations - vendor-agnostic guidance for reducing exposure to this technique.
M1017User Training

User Training involves educating employees and contractors on recognizing, reporting, and preventing cyber threats that rely on human interaction, such as phishing, social engineering, and other manipulative techniques. Comprehensive training programs create a human firewall by empowering users to be an active component of the organization's cybersecurity defenses.

Create Comprehensive Training Programs
  • Design training modules tailored to the organization's risk profile, covering topics such as phishing, password management, and incident reporting.
  • Provide role-specific training for high-risk employees, such as helpdesk staff or executives.
Use Simulated Exercises
  • Conduct phishing simulations to measure user susceptibility and provide targeted follow-up training.
  • Run social engineering drills to evaluate employee responses and reinforce protocols.
Leverage Gamification and Engagement
  • Introduce interactive learning methods such as quizzes, gamified challenges, and rewards for successful detection and reporting of threats.
Incorporate Security Policies into Onboarding
  • Include cybersecurity training as part of the onboarding process for new employees.
  • Provide easy-to-understand materials outlining acceptable use policies and reporting procedures.
Regular Refresher Courses
  • Update training materials to include emerging threats and techniques used by adversaries.
  • Ensure all employees complete periodic refresher courses to stay informed.
Emphasize Real-World Scenarios
  • Use case studies of recent attacks to demonstrate the consequences of successful phishing or social engineering.
  • Discuss how specific employee actions can prevent or mitigate such attacks.
M1030Network Segmentation

Network segmentation involves dividing a network into smaller, isolated segments to control and limit the flow of traffic between devices, systems, and applications. By segmenting networks, organizations can reduce the attack surface, restrict lateral movement by adversaries, and protect critical assets from compromise. Effective network segmentation leverages a combination of physical boundaries, logical separation through VLANs, and access control policies enforced by network appliances like firewalls, routers, and cloud-based configurations.

Segment Critical Systems
  • Identify and group systems based on their function, sensitivity, and risk. Examples include payment systems, HR databases, production systems, and internet-facing servers.
  • Use VLANs, firewalls, or routers to enforce logical separation.
Implement DMZ for Public-Facing Services
  • Host web servers, DNS servers, and email servers in a DMZ to limit their access to internal systems.
  • Apply strict firewall rules to filter traffic between the DMZ and internal networks.
Use Cloud-Based Segmentation
  • In cloud environments, use VPCs, subnets, and security groups to isolate applications and enforce traffic rules.
  • Apply AWS Transit Gateway or Azure VNet peering for controlled connectivity between cloud segments.
Apply Microsegmentation for Workloads
  • Use software-defined networking (SDN) tools to implement workload-level segmentation and prevent lateral movement.
Restrict Traffic with ACLs and Firewalls
  • Apply Access Control Lists (ACLs) to network devices to enforce "deny by default" policies.
  • Use firewalls to restrict both north-south (external-internal) and east-west (internal-internal) traffic.
Monitor and Audit Segmented Networks
  • Regularly review firewall rules, ACLs, and segmentation policies.
  • Monitor network flows for anomalies to ensure segmentation is effective.
Test Segmentation Effectiveness
  • Perform periodic penetration tests to verify that unauthorized access is blocked between network segments.
M1031Network Intrusion Prevention

Use intrusion detection signatures to block traffic at network boundaries.

M1035Limit Access to Resource Over Network

Restrict access to network resources, such as file shares, remote systems, and services, to only those users, accounts, or systems with a legitimate business requirement. This can include employing technologies like network concentrators, RDP gateways, and zero-trust network access (ZTNA) models, alongside hardening services and protocols.

Audit and Restrict Access
  • Regularly audit permissions for file shares, network services, and remote access tools.
  • Remove unnecessary access and enforce least privilege principles for users and services.
  • Use Active Directory and IAM tools to restrict access based on roles and attributes.
Deploy Secure Remote Access Solutions
  • Use RDP gateways, VPN concentrators, and ZTNA solutions to aggregate and secure remote access connections.
  • Configure access controls to restrict connections based on time, device, and user identity.
  • Enforce MFA for all remote access mechanisms.
Disable Unnecessary Services
  • Identify running services using tools like netstat (Windows/Linux) or Nmap.
  • Disable unused services, such as Telnet, FTP, and legacy SMB, to reduce the attack surface.
  • Use firewall rules to block traffic on unused ports and protocols.
Network Segmentation and Isolation
  • Use VLANs, firewalls, or micro-segmentation to isolate critical network resources from general access.
  • Restrict communication between subnets to prevent lateral movement.
Monitor and Log Access
  • Monitor access attempts to file shares, RDP, and remote network resources using SIEM tools.
  • Enable auditing and logging for successful and failed attempts to access restricted resources.
Tools for Implementation File Share Management
  • Microsoft Active Directory Group Policies.
  • Samba (Linux/Unix file share management)
AccessEnum (Windows access auditing tool) Secure Remote Access
  • Microsoft Remote Desktop Gateway.
  • Apache Guacamole (open-source RDP/VNC gateway)
  • Zero Trust solutions: Tailscale, Cloudflare Zero Trust Service and Protocol Hardening:.
  • Nmap or Nessus for network service discovery.
  • Windows Group Policy Editor for disabling SMBv1, Telnet, and legacy protocols.
  • iptables or firewalld (Linux) for blocking unnecessary traffic Network Segmentation:.
  • pfSense for open-source network isolation.
M1037Filter Network Traffic

Employ network appliances and endpoint software to filter ingress, egress, and lateral network traffic. This includes protocol-based filtering, enforcing firewall rules, and blocking or restricting traffic based on predefined conditions to limit adversary movement and data exfiltration.

Ingress Traffic Filtering
  • Use Case: Configure network firewalls to allow traffic only from authorized IP addresses to public-facing servers.
  • Implementation: Limit SSH (port 22) and RDP (port 3389) traffic to specific IP ranges.
Egress Traffic Filtering
  • Use Case: Use firewalls or endpoint security software to block unauthorized outbound traffic to prevent data exfiltration and command-and-control (C2) communications.
  • Implementation: Block outbound traffic to known malicious IPs or regions where communication is unexpected.
Protocol-Based Filtering
  • Use Case: Restrict the use of specific protocols that are commonly abused by adversaries, such as SMB, RPC, or Telnet, based on business needs.
  • Implementation: Disable SMBv1 on endpoints to prevent exploits like EternalBlue.
Network Segmentation
  • Use Case: Create network segments for critical systems and restrict communication between segments unless explicitly authorized.
  • Implementation: Implement VLANs to isolate IoT devices or guest networks from core business systems.
Application Layer Filtering
  • Use Case: Use proxy servers or Web Application Firewalls (WAFs) to inspect and block malicious HTTP/S traffic.
  • Implementation: Configure a WAF to block SQL injection attempts or other web application exploitation techniques.
M1041Encrypt Sensitive Information

Protect sensitive information at rest, in transit, and during processing by using strong encryption algorithms. Encryption ensures the confidentiality and integrity of data, preventing unauthorized access or tampering.

Encrypt Data at Rest
  • Use Case: Use full-disk encryption or file-level encryption to secure sensitive data stored on devices.
  • Implementation: Implement BitLocker for Windows systems or FileVault for macOS devices to encrypt hard drives.
Encrypt Data in Transit
  • Use Case: Use secure communication protocols (e.g., TLS, HTTPS) to encrypt sensitive data as it travels over networks.
  • Implementation: Enable HTTPS for all web applications and configure mail servers to enforce STARTTLS for email encryption.
Encrypt Backups
  • Use Case: Ensure that backup data is encrypted both during storage and transfer to prevent unauthorized access.
  • Implementation: Encrypt cloud backups using AES-256 before uploading them to Amazon S3 or Google Cloud.
Encrypt Application Secrets
  • Use Case: Store sensitive credentials, API keys, and configuration files in encrypted vaults.
  • Implementation: Use HashiCorp Vault or AWS Secrets Manager to manage and encrypt secrets.
Database Encryption
  • Use Case: Enable Transparent Data Encryption (TDE) or column-level encryption in database management systems.
  • Implementation: Use MySQL’s built-in encryption features to encrypt sensitive database fields such as social security numbers.
M1042Disable or Remove Feature or Program

Disable or remove unnecessary and potentially vulnerable software, features, or services to reduce the attack surface and prevent abuse by adversaries. This involves identifying software or features that are no longer needed or that could be exploited and ensuring they are either removed or properly disabled.

Remove Legacy Software
  • Use Case: Disable or remove older versions of software that no longer receive updates or security patches (e.g., legacy Java, Adobe Flash).
  • Implementation: A company removes Flash Player from all employee systems after it has reached its end-of-life date.
Disable Unused Features
  • Use Case: Turn off unnecessary operating system features like SMBv1, Telnet, or RDP if they are not required.
  • Implementation: Disable SMBv1 in a Windows environment to mitigate vulnerabilities like EternalBlue.
Control Applications Installed by Users
  • Use Case: Prevent users from installing unauthorized software via group policies or other management tools.
  • Implementation: Block user installations of unauthorized file-sharing applications (e.g., BitTorrent clients) in an enterprise environment.
Remove Unnecessary Services
  • Use Case: Identify and disable unnecessary default services running on endpoints, servers, or network devices.
  • Implementation: Disable unused administrative shares (e.g., C$, ADMIN$) on workstations.
Restrict Add-ons and Plugins
  • Use Case: Remove or disable browser plugins and add-ons that are not needed for business purposes.
  • Implementation: Disable Java and ActiveX plugins in web browsers to prevent drive-by attacks.

Detection Coverage

1/6 layers
Coverage across standard detection surfaces. Rows marked none have no rule of that type mapped. Some are real blind spots worth closing; others are simply not applicable to this technique (e.g. YARA matches malware files, not network behaviour).
Behavioral / log (Sigma) 9
Analytics (MITRE CAR) none
Runtime / container (Falco) none
File / malware (YARA) none
Network (Suricata/Snort) none
Vuln scan (Nuclei) none
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