Indicator Removal on Host: Clear Windows Event Logs

Adversaries may clear Windows Event Logs to hide the activity of an intrusion. Windows Event Logs are a record of a computer's alerts and notifications. There are three system-defined sources of events: System, Application, and Security, with five event types: Error, Warning, Information, Success Audit, and Failure Audit.

The event logs can be cleared with the following utility commands:

  • wevtutil cl system
  • wevtutil cl application
  • wevtutil cl security

These logs may also be cleared through other mechanisms, such as the event viewer GUI or PowerShell.

ID: T1070.001
Sub-technique of:  T1070
Tactic: Defense Evasion
Platforms: Windows
System Requirements: Clearing the Windows event logs requires Administrator permissions
Permissions Required: Administrator
Data Sources: Command: Command Execution, Process: OS API Execution
Defense Bypassed: Anti Virus, Host Intrusion Prevention Systems, Log Analysis
Version: 1.0
Created: 28 January 2020
Last Modified: 29 March 2020

Procedure Examples

ID Name Description
G0007 APT28

APT28 has cleared event logs, including by using the commands wevtutil cl System and wevtutil cl Security.[1][2]

G0050 APT32

APT32 has cleared select event log entries.[3]

G0082 APT38

APT38 clears Window Event logs and Sysmon logs from the system.[4]

G0096 APT41

APT41 attempted to remove evidence of some of its activity by clearing Windows security and system events.[5]

S0089 BlackEnergy

The BlackEnergy component KillDisk is capable of deleting Windows Event Logs.[6]

G0114 Chimera

Chimera has cleared event logs on compromised hosts.[7]

G0074 Dragonfly 2.0

Dragonfly 2.0 cleared Windows event logs and other logs produced by tools they used, including system, security, terminal services, remote services, and audit logs. The actors also deleted specific Registry keys.[8][9]

G0053 FIN5

FIN5 has cleared event logs from victims.[10]

G0061 FIN8

FIN8 has cleared logs during post compromise cleanup activities.[11]

S0182 FinFisher

FinFisher clears the system event logs using OpenEventLog/ClearEventLog APIs .[12][13]

S0032 gh0st RAT

gh0st RAT is able to wipe event logs.[14][15]

S0203 Hydraq

Hydraq creates a backdoor through which remote attackers can clear all system event logs.[16][17]

S0532 Lucifer

Lucifer can clear and remove event logs.[18]

S0368 NotPetya

NotPetya uses wevtutil to clear the Windows event logs.[19][20]

S0365 Olympic Destroyer

Olympic Destroyer will attempt to clear the System and Security event logs using wevtutil.[21]

G0116 Operation Wocao

Operation Wocao has deleted Windows Event Logs to hinder forensic investigation.[22]

S0192 Pupy

Pupy has a module to clear event logs with PowerShell.[23]

S0253 RunningRAT

RunningRAT contains code to clear event logs.[24]

S0242 SynAck

SynAck clears event logs.[25]

S0412 ZxShell

ZxShell has a command to clear system event logs.[26]

Mitigations

ID Mitigation Description
M1041 Encrypt Sensitive Information

Obfuscate/encrypt event files locally and in transit to avoid giving feedback to an adversary.

M1029 Remote Data Storage

Automatically forward events to a log server or data repository to prevent conditions in which the adversary can locate and manipulate data on the local system. When possible, minimize time delay on event reporting to avoid prolonged storage on the local system.

M1022 Restrict File and Directory Permissions

Protect generated event files that are stored locally with proper permissions and authentication and limit opportunities for adversaries to increase privileges by preventing Privilege Escalation opportunities.

Detection

Deleting Windows event logs (via native binaries [27], API functions [28], or PowerShell [29]) may also generate an alterable event (Event ID 1102: "The audit log was cleared").

References

  1. Alperovitch, D.. (2016, June 15). Bears in the Midst: Intrusion into the Democratic National Committee. Retrieved August 3, 2016.
  2. Mueller, R. (2018, July 13). Indictment - United States of America vs. VIKTOR BORISOVICH NETYKSHO, et al. Retrieved September 13, 2018.
  3. Carr, N.. (2017, May 14). Cyber Espionage is Alive and Well: APT32 and the Threat to Global Corporations. Retrieved June 18, 2017.
  4. FireEye. (2018, October 03). APT38: Un-usual Suspects. Retrieved November 6, 2018.
  5. Fraser, N., et al. (2019, August 7). Double DragonAPT41, a dual espionage and cyber crime operation APT41. Retrieved September 23, 2019.
  6. Cherepanov, A.. (2016, January 3). BlackEnergy by the SSHBearDoor: attacks against Ukrainian news media and electric industry. Retrieved May 18, 2016.
  7. Jansen, W . (2021, January 12). Abusing cloud services to fly under the radar. Retrieved January 19, 2021.
  8. US-CERT. (2018, March 16). Alert (TA18-074A): Russian Government Cyber Activity Targeting Energy and Other Critical Infrastructure Sectors. Retrieved June 6, 2018.
  9. US-CERT. (2017, October 20). Alert (TA17-293A): Advanced Persistent Threat Activity Targeting Energy and Other Critical Infrastructure Sectors. Retrieved November 2, 2017.
  10. Bromiley, M. and Lewis, P. (2016, October 7). Attacking the Hospitality and Gaming Industries: Tracking an Attacker Around the World in 7 Years. Retrieved October 6, 2017.
  11. Elovitz, S. & Ahl, I. (2016, August 18). Know Your Enemy: New Financially-Motivated & Spear-Phishing Group. Retrieved February 26, 2018.
  12. FinFisher. (n.d.). Retrieved December 20, 2017.
  13. Allievi, A.,Flori, E. (2018, March 01). FinFisher exposed: A researcher’s tale of defeating traps, tricks, and complex virtual machines. Retrieved July 9, 2018.
  14. FireEye Threat Intelligence. (2015, July 13). Demonstrating Hustle, Chinese APT Groups Quickly Use Zero-Day Vulnerability (CVE-2015-5119) Following Hacking Team Leak. Retrieved January 25, 2016.
  15. Quinn, J. (2019, March 25). The odd case of a Gh0stRAT variant. Retrieved July 15, 2020.
  1. Symantec Security Response. (2010, January 18). The Trojan.Hydraq Incident. Retrieved February 20, 2018.
  2. Lelli, A. (2010, January 11). Trojan.Hydraq. Retrieved February 20, 2018.
  3. Hsu, K. et al. (2020, June 24). Lucifer: New Cryptojacking and DDoS Hybrid Malware Exploiting High and Critical Vulnerabilities to Infect Windows Devices. Retrieved November 16, 2020.
  4. Chiu, A. (2016, June 27). New Ransomware Variant "Nyetya" Compromises Systems Worldwide. Retrieved March 26, 2019.
  5. Scott W. Brady. (2020, October 15). United States vs. Yuriy Sergeyevich Andrienko et al.. Retrieved November 25, 2020.
  6. Mercer, W. and Rascagneres, P. (2018, February 12). Olympic Destroyer Takes Aim At Winter Olympics. Retrieved March 14, 2019.
  7. Dantzig, M. v., Schamper, E. (2019, December 19). Operation Wocao: Shining a light on one of China’s hidden hacking groups. Retrieved October 8, 2020.
  8. Nicolas Verdier. (n.d.). Retrieved January 29, 2018.
  9. Sherstobitoff, R., Saavedra-Morales, J. (2018, February 02). Gold Dragon Widens Olympics Malware Attacks, Gains Permanent Presence on Victims’ Systems. Retrieved June 6, 2018.
  10. Ivanov, A. et al.. (2018, May 7). SynAck targeted ransomware uses the Doppelgänging technique. Retrieved May 22, 2018.
  11. Allievi, A., et al. (2014, October 28). Threat Spotlight: Group 72, Opening the ZxShell. Retrieved September 24, 2019.
  12. Plett, C. et al.. (2017, October 16). wevtutil. Retrieved July 2, 2018.
  13. Microsoft. (n.d.). EventLog.Clear Method (). Retrieved July 2, 2018.
  14. Microsoft. (n.d.). Clear-EventLog. Retrieved July 2, 2018.