Suspicious Content Extracted or Decompressed via Funzip

Last updated 5 months ago on 2025-03-20
Created 2 years ago on 2023-06-26

About

Identifies when suspicious content is extracted from a file and subsequently decompressed using the funzip utility. Malware may execute the tail utility using the "-c" option to read a sequence of bytes from the end of a file. The output from tail can be piped to funzip in order to decompress malicious code before it is executed. This behavior is consistent with malware families such as Bundlore.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: ExecutionData Source: Elastic EndgameData Source: Elastic DefendData Source: SentinelOneLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Execution (TA0002)(opens in a new tab or window)

Defense Evasion (TA0005)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
endgame-*logs-endpoint.events.process*logs-sentinel_one_cloud_funnel.*
Related Integrations

endpoint(opens in a new tab or window)

sentinel_one_cloud_funnel(opens in a new tab or window)

Query
process where host.os.type == "linux" and event.action in ("exec", "exec_event", "start") and
((process.args == "tail" and process.args == "-c" and process.args == "funzip")) and
not process.args : "/var/log/messages" and
not process.parent.executable : ("/usr/bin/dracut", "/sbin/dracut", "/usr/bin/xargs") and
not (process.parent.name in ("sh", "sudo") and process.parent.command_line : "*nessus_su*")

Install detection rules in Elastic Security

Detect Suspicious Content Extracted or Decompressed via Funzip in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).