Dynamic Linker Copy

Detects the copying of the Linux dynamic loader binary and subsequent file creation for the purpose of creating a backup copy. This technique was seen recently being utilized by Linux malware prior to patching the dynamic loader in order to inject and preload a malicious shared object file. This activity should never occur and if it does then it should be considered highly suspicious or malicious.

Rule type: eql

Rule indices:

Severity: high

Risk score: 85

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

Version: 2

Rule authors:

Rule license: Elastic License v2

sequence by process.entity_id with maxspan=1m
[process where event.type == "start" and process.name : ("cp", "rsync") and process.args : ("/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2", "/etc/ld.so.preload")]
[file where event.action == "creation" and file.extension == "so"]