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TECHNIQUES
PRE-ATT&CK
Priority Definition Planning
Priority Definition Direction
Target Selection
Technical Information Gathering
People Information Gathering
Organizational Information Gathering
Technical Weakness Identification
People Weakness Identification
Organizational Weakness Identification
Adversary OPSEC
Establish & Maintain Infrastructure
Persona Development
Build Capabilities
Test Capabilities
Stage Capabilities
Enterprise
Initial Access
Phishing
Supply Chain Compromise
Valid Accounts
Execution
Command and Scripting Interpreter
Inter-Process Communication
Scheduled Task/Job
System Services
User Execution
Persistence
Account Manipulation
Boot or Logon Autostart Execution
Boot or Logon Initialization Scripts
Create Account
Create or Modify System Process
Event Triggered Execution
Hijack Execution Flow
Office Application Startup
Pre-OS Boot
Scheduled Task/Job
Server Software Component
Traffic Signaling
Valid Accounts
Privilege Escalation
Abuse Elevation Control Mechanism
Access Token Manipulation
Boot or Logon Autostart Execution
Boot or Logon Initialization Scripts
Create or Modify System Process
Event Triggered Execution
Hijack Execution Flow
Process Injection
Scheduled Task/Job
Valid Accounts
Defense Evasion
Abuse Elevation Control Mechanism
Access Token Manipulation
Execution Guardrails
File and Directory Permissions Modification
Hide Artifacts
Hijack Execution Flow
Impair Defenses
Indicator Removal on Host
Masquerading
Modify Authentication Process
Modify Cloud Compute Infrastructure
Obfuscated Files or Information
Pre-OS Boot
Process Injection
Signed Binary Proxy Execution
Signed Script Proxy Execution
Subvert Trust Controls
Traffic Signaling
Trusted Developer Utilities Proxy Execution
Use Alternate Authentication Material
Valid Accounts
Virtualization/Sandbox Evasion
Credential Access
Brute Force
Credentials from Password Stores
Input Capture
Man-in-the-Middle
Modify Authentication Process
OS Credential Dumping
Steal or Forge Kerberos Tickets
Unsecured Credentials
Discovery
Account Discovery
Permission Groups Discovery
Software Discovery
Virtualization/Sandbox Evasion
Lateral Movement
Remote Service Session Hijacking
Remote Services
Use Alternate Authentication Material
Collection
Archive Collected Data
Data from Information Repositories
Data Staged
Email Collection
Input Capture
Man-in-the-Middle
Command and Control
Application Layer Protocol
Data Encoding
Data Obfuscation
Dynamic Resolution
Encrypted Channel
Proxy
Traffic Signaling
Web Service
Exfiltration
Exfiltration Over Alternative Protocol
Exfiltration Over Other Network Medium
Exfiltration Over Physical Medium
Exfiltration Over Web Service
Impact
Data Manipulation
Defacement
Disk Wipe
Endpoint Denial of Service
Network Denial of Service
Mobile
Initial Access
Execution
Persistence
Privilege Escalation
Defense Evasion
Credential Access
Discovery
Lateral Movement
Collection
Command and Control
Exfiltration
Impact
Network Effects
Remote Service Effects
  1. Home
  2. Techniques
  3. Enterprise
  4. Data Transfer Size Limits

Data Transfer Size Limits

An adversary may exfiltrate data in fixed size chunks instead of whole files or limit packet sizes below certain thresholds. This approach may be used to avoid triggering network data transfer threshold alerts.

ID: T1030
Sub-techniques:  No sub-techniques
Tactic: Exfiltration
Platforms: Linux, Windows, macOS
Data Sources: Netflow/Enclave netflow, Packet capture, Process monitoring, Process use of network
Requires Network:  Yes
Version: 1.0
Created: 31 May 2017
Last Modified: 14 July 2020

Procedure Examples

Name Description
Carbanak

Carbanak exfiltrates data in compressed chunks if a message is larger than 4096 bytes .[4]
Helminth

Helminth splits data into chunks up to 23 bytes and sends the data in DNS queries to its C2 server.[3]
OopsIE

OopsIE exfiltrates command output and collected files to its C2 server in 1500-byte blocks.[2]
POSHSPY

POSHSPY uploads data in 2048-byte chunks.[1]
Threat Group-3390

Threat Group-3390 actors have split RAR files for exfiltration into parts.[5]

Mitigations

Mitigation Description
Network Intrusion Prevention

Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary command and control infrastructure and malware can be used to mitigate activity at the network level.

Detection

Analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server). If a process maintains a long connection during which it consistently sends fixed size data packets or a process opens connections and sends fixed sized data packets at regular intervals, it may be performing an aggregate data transfer. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used. [6]

References

  1. Dunwoody, M.. (2017, April 3). Dissecting One of APT29’s Fileless WMI and PowerShell Backdoors (POSHSPY). Retrieved April 5, 2017.
  2. Lee, B., Falcone, R. (2018, February 23). OopsIE! OilRig Uses ThreeDollars to Deliver New Trojan. Retrieved July 16, 2018.
  3. Falcone, R. and Lee, B.. (2016, May 26). The OilRig Campaign: Attacks on Saudi Arabian Organizations Deliver Helminth Backdoor. Retrieved May 3, 2017.
  1. Bennett, J., Vengerik, B. (2017, June 12). Behind the CARBANAK Backdoor. Retrieved June 11, 2018.
  2. Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.
  3. Gardiner, J., Cova, M., Nagaraja, S. (2014, February). Command & Control Understanding, Denying and Detecting. Retrieved April 20, 2016.