Indicator Removal on Host

Adversaries may delete or alter generated artifacts on a host system, including logs or captured files such as quarantined malware. Locations and format of logs are platform or product-specific, however standard operating system logs are captured as Windows events or Linux/macOS files such as Bash History and /var/log/*.

These actions may interfere with event collection, reporting, or other notifications used to detect intrusion activity. This that may compromise the integrity of security solutions by causing notable events to go unreported. This activity may also impede forensic analysis and incident response, due to lack of sufficient data to determine what occurred.

ID: T1551
Tactic: Defense Evasion
Platforms: Linux, Windows, macOS
Data Sources: API monitoring, File monitoring, Process command-line parameters, Process monitoring, Windows event logs
Defense Bypassed: Anti-virus, Host intrusion prevention systems, Log analysis
CAPEC ID: CAPEC-93
Contributors: Ed Williams, Trustwave, SpiderLabs
Version: 1.1
Created: 31 May 2017
Last Modified: 29 March 2020

Procedure Examples

Name Description
Bankshot

Bankshot deletes all artifacts associated with the malware from the infected machine.[3]

Misdat

Misdat is capable of deleting Registry keys used for persistence.[4]

Orz

Orz can overwrite Registry settings to reduce its visibility on the victim.[1]

Prikormka

After encrypting its own log files, the log encryption module in Prikormka deletes the original, unencrypted files from the host.[5]

RTM

RTM has the ability to remove Registry entries that it created during execution.[2]

Mitigations

Mitigation Description
Encrypt Sensitive Information

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

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.

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

File system monitoring may be used to detect improper deletion or modification of indicator files. Events not stored on the file system may require different detection mechanisms.

References