Ingress Tool Transfer

Ingress Tool Transfer [T1105]

Information

• Name: Ingress Tool Transfer

• ID: T1105

• Tactics: TA0011

Introduction

Ingress Tool Transfer is a technique categorized under the MITRE ATT&CK framework (T1105), referring to adversaries transferring malicious tools or payloads into a compromised environment. Attackers commonly leverage this technique to introduce additional malware, scripts, or utilities required to escalate privileges, maintain persistence, or conduct lateral movement. Typically, ingress tool transfer involves downloading files from external sources, transferring files over command-and-control (C2) channels, or using native protocols to introduce malicious payloads into a victim's network.

Deep Dive Into Technique

Ingress Tool Transfer involves several technical mechanisms and execution methods, including:

• File Downloads via HTTP/HTTPS: Attackers frequently use standard web protocols to download malicious payloads onto compromised systems. Tools like curl, wget, PowerShell commands (Invoke-WebRequest), and Windows BITSAdmin are commonly abused.

• FTP/SFTP/SCP Transfers: Attackers may leverage FTP or secure file transfer protocols to transfer malicious binaries or scripts onto victim machines, often exploiting legitimate administrative tools or compromised credentials.

• Command-and-Control (C2) Channels: Adversaries often use established C2 communication channels to upload additional tools directly onto compromised systems. These channels might include custom protocols, DNS tunneling, or encrypted sessions.

• Email Attachments or Cloud Storage Services: Attackers may deliver payloads through email attachments or legitimate cloud storage services (e.g., Dropbox, Google Drive, OneDrive), leveraging trusted services to bypass security controls.

• Encoded Payload Transfer: Malicious payloads are sometimes encoded (Base64, hexadecimal) or encrypted during transfer to evade detection mechanisms. Once transferred, attackers decode or decrypt payloads on compromised systems.

Real-world procedures commonly involve:

• Using built-in utilities (certutil.exe, bitsadmin.exe, PowerShell) to download payloads.

• Exploiting web shells or remote access trojans (RATs) to transfer tools.

• Leveraging compromised administrative credentials to transfer payloads via SMB or remote desktop protocols.

When this Technique is Usually Used

Ingress Tool Transfer can appear in multiple attack scenarios and stages, including:

• Initial Access and Execution Stage: Attackers may initially transfer payloads immediately after gaining access through phishing, exploitation, or credential theft.

• Persistence and Privilege Escalation: Adversaries transfer specialized tools or scripts to escalate privileges or establish persistent footholds.

• Lateral Movement and Internal Reconnaissance: Attackers frequently transfer reconnaissance tools or lateral movement utilities (such as Mimikatz, PsExec, BloodHound) to move within compromised environments.

• Exfiltration and Data Theft: Attackers may transfer specialized exfiltration tools or scripts designed to compress, encrypt, and transfer stolen data.

• Post-Exploitation and Cleanup: Attackers may transfer tools that facilitate cleanup and cover their tracks, deleting logs or artifacts.

How this Technique is Usually Detected

Detection methods, tools, and indicators of compromise (IoCs) for Ingress Tool Transfer include:

• Network Traffic Analysis:

  • Monitoring unusual outbound/inbound HTTP(S), FTP, or DNS traffic patterns.

  • Detecting unexpected downloads from external IP addresses or domains.

  • Identifying abnormal file transfers through protocol analysis tools (Wireshark, Zeek/Bro).

• Endpoint Detection and Response (EDR) Solutions:

  • Detecting suspicious execution of built-in utilities (certutil, bitsadmin, PowerShell) initiating external downloads.

  • Monitoring process creation events and command-line parameters for suspicious transfer activity.

• File Integrity Monitoring (FIM):

  • Identifying unexpected file creations or modifications in sensitive directories.

• Proxy and Firewall Log Analysis:

  • Reviewing proxy logs for unusual file downloads or accesses to suspicious domains.

  • Identifying firewall logs indicating unauthorized outbound connections.

• Behavioral Analytics and SIEM Correlation:

  • Correlating multiple events (network, endpoint, authentication) to detect anomalous ingress transfers.

  • Alerting on encoded or obfuscated payload downloads.

Specific Indicators of Compromise (IoCs):

• Suspicious URLs or domains known for malware distribution.

• Unusual files or scripts appearing in temporary directories (/tmp, %TEMP%).

• Usage of uncommon or suspicious user-agent strings in HTTP requests.

• Unexpected binaries or scripts downloaded via native tools (certutil.exe, bitsadmin.exe, PowerShell scripts).

Why it is Important to Detect This Technique

Detecting Ingress Tool Transfer is critical due to its significant impact on systems and networks:

• Early Detection of Intrusions: Identifying ingress transfers promptly helps security teams detect intrusions at early stages, limiting attacker dwell time.

• Preventing Privilege Escalation and Persistence: Detecting malicious payload transfers prevents attackers from escalating privileges or establishing persistent footholds.

• Reducing Risk of Lateral Movement: Early detection limits attackers' ability to move laterally and compromise additional systems or sensitive data.

• Preventing Data Exfiltration and Loss: Identifying and preventing ingress transfers reduces the risk of attackers successfully transferring exfiltration tools, thus protecting sensitive data.

• Reducing Incident Response Costs and Complexity: Early detection minimizes remediation efforts, reducing costs and complexity associated with incident response and forensic investigations.

Examples

Real-world examples demonstrating Ingress Tool Transfer include:

1. APT29 (Cozy Bear) - SolarWinds Supply Chain Attack:

   • Scenario: After initial compromise through SolarWinds Orion updates, attackers transferred additional tools and malware payloads using HTTP(S) channels.

   • Tools: Cobalt Strike, Teardrop malware, customized PowerShell scripts.

   • Impact: Extensive compromise of multiple U.S. government agencies and private organizations, leading to significant data theft and espionage.

2. APT41 - Operation CuckooBees:

   • Scenario: Attackers leveraged legitimate cloud storage services (Dropbox, Google Drive) to transfer malicious payloads onto targeted systems.

   • Tools: China Chopper web shells, PlugX malware, custom PowerShell scripts.

   • Impact: Theft of intellectual property, sensitive business data, and extended persistence within victim environments.

3. FIN7 Financial Threat Actor:

   • Scenario: Attackers transferred malicious payloads via phishing emails containing malicious attachments or links leading to downloads.

   • Tools: Carbanak malware, Cobalt Strike beacons, customized reconnaissance utilities.

   • Impact: Extensive financial fraud, theft of payment card information, and significant financial losses for targeted organizations.

4. Ransomware Operators (e.g., Conti, Ryuk):

   • Scenario: Attackers transferred ransomware payloads via compromised remote desktop (RDP) sessions or phishing campaigns.

   • Tools: Cobalt Strike, Ryuk ransomware, Conti ransomware, PowerShell scripts.

   • Impact: Severe business disruption, operational downtime, extensive financial losses due to ransom demands, and reputational damage.

These examples highlight the diverse methods, tools, and severe impacts associated with Ingress Tool Transfer, emphasizing the importance of proactive detection and prevention.