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ATT&CK Technique

Mail Protocols

T1071.003 · command-and-control

Adversaries may communicate using application layer protocols associated with electronic mail delivery to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server. Protocols such as SMTP/S, POP3/S, and IMAP that carry electronic mail may be very common in environments.

Packets produced from these protocols may have many fields and headers in which data can be concealed. Data could also be concealed within the email messages themselves. An adversary may abuse these protocols to communicate with systems under their control within a victim network while also mimicking normal, expected traffic.

LinuxmacOSNetwork DevicesWindows
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Actors Using This

14
north_koreaAndariel
russiaAPT28
iranOilRig
iranAPT35
north_koreaAPT37
north_koreaAPT38
iranAPT39
north_koreaContagious Interview
chinaEarth Alux
chinaFlax Typhoon
chinaGALLIUM
russiaGamaredon Group
iranImperial Kitten
north_koreaKimsuky
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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.
reconnaissance earlier
T1598.002 · Spearphishing Attachment ×9.52T1589.002 · Email Addresses ×6.21
resource-development earlier
T1584.006 · Web Services ×7.14
execution earlier
T1559.002 · Dynamic Data Exchange ×6.80
persistence earlier
T1137.006 · Add-ins ×9.52T1137 · Office Application Startup ×6.80
privilege-escalation earlier
T1546.001 · Change Default File Association ×9.52T1546.011 · Application Shimming ×8.57T1546.015 · Component Object Model Hijacking ×8.57
credential-access earlier
T1555.004 · Windows Credential Manager ×8.33
discovery earlier
T1087.003 · Email Account ×7.93T1120 · Peripheral Device Discovery ×6.80
collection earlier
T1213.002 · Sharepoint ×6.35T1602 · Data from Configuration Repository ×6.35
command-and-control same
T1008 · Fallback Channels ×6.35
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Mitigations

2
MITRE ATT&CK mitigations - vendor-agnostic guidance for reducing exposure to this technique.
M1031Network Intrusion Prevention

Use intrusion detection signatures to block traffic at network boundaries.

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.
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Detection Coverage

0/6 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) none
Analytics (MITRE CAR) none
Runtime / container (Falco) none
File / malware (YARA) none
Network (Suricata/Snort) none
Vuln scan (Nuclei) none
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Comply & Defend

NIST 800-53AC-04, CA-07, CM-02, CM-06, CM-07, SC-07, SC-10, SC-20, SC-21, SC-22, SC-23, SC-31, SC-37, SI-03, SI-04
D3FEND11 defensive techniques
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
MITRE ATT&CKAtomic Red Teamcar (MITRE)
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