Jonhnathan
84 lines
3.3 KiB
TOML
84 lines
3.3 KiB
TOML
[metadata]
|
|
creation_date = "2020/11/29"
|
|
maturity = "production"
|
|
updated_date = "2022/04/13"
|
|
|
|
[rule]
|
|
author = ["Elastic"]
|
|
description = """
|
|
Identifies built-in Windows script interpreters (cscript.exe or wscript.exe) being used to download an executable file
|
|
from a remote destination.
|
|
"""
|
|
from = "now-9m"
|
|
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
|
|
language = "eql"
|
|
license = "Elastic License v2"
|
|
name = "Remote File Download via Script Interpreter"
|
|
note = """## Triage and analysis
|
|
|
|
### Investigating Remote File Download via Script Interpreter
|
|
|
|
The Windows Script Host (WSH) is a Windows automation technology, which is ideal for non-interactive scripting needs,
|
|
such as logon scripting, administrative scripting, and machine automation.
|
|
|
|
Attackers commonly use WSH scripts as their initial access method, acting like droppers for second stage payloads, but
|
|
can also use them to download tools and utilities needed to accomplish their goals.
|
|
|
|
This rule looks for DLLs and executables downloaded using `cscript.exe` or `wscript.exe`.
|
|
|
|
#### Possible investigation steps
|
|
|
|
- Investigate the process execution chain (parent process tree).
|
|
- Retrieve the script file and the executable involved:
|
|
- Use a sandboxed malware analysis system to perform analysis.
|
|
- Observe attempts to contact external domains and addresses.
|
|
- Use the PowerShell Get-FileHash cmdlet to get the SHA-256 hash value of the file.
|
|
- Search for the existence and reputation of this file in resources like VirusTotal, Hybrid-Analysis, CISCO Talos, Any.run, etc.
|
|
- Manually analyze the script to determine if malicious capabilities are present.
|
|
- Investigate whether the potential malware ran successfully, is active on the host, or was stopped by defenses.
|
|
- Investigate other alerts related to the user/host in the last 48 hours.
|
|
- Check for similar behavior in other hosts on the environment.
|
|
|
|
### False positive analysis
|
|
|
|
- The usage of these script engines by regular users is unlikely. In the case of authorized benign true positives
|
|
(B-TPs), exceptions can be added.
|
|
|
|
### Response and remediation
|
|
|
|
- Initiate the incident response process based on the outcome of the triage.
|
|
- Isolate the involved host to prevent further post-compromise behavior.
|
|
- If the triage identified malware, search the environment for additional compromised hosts.
|
|
- Implement any temporary network rules, procedures, and segmentation required to contain the malware.
|
|
- Remove and block malicious artifacts identified on the triage.
|
|
- Reimage the host operating system and restore compromised files to clean versions.
|
|
"""
|
|
risk_score = 47
|
|
rule_id = "1d276579-3380-4095-ad38-e596a01bc64f"
|
|
severity = "medium"
|
|
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Command and Control"]
|
|
type = "eql"
|
|
|
|
query = '''
|
|
sequence by host.id, process.entity_id
|
|
[network where process.name : ("wscript.exe", "cscript.exe") and network.protocol != "dns" and
|
|
network.direction : ("outgoing", "egress") and network.type == "ipv4" and destination.ip != "127.0.0.1"
|
|
]
|
|
[file where event.type == "creation" and file.extension : ("exe", "dll")]
|
|
'''
|
|
|
|
|
|
[[rule.threat]]
|
|
framework = "MITRE ATT&CK"
|
|
[[rule.threat.technique]]
|
|
id = "T1105"
|
|
name = "Ingress Tool Transfer"
|
|
reference = "https://attack.mitre.org/techniques/T1105/"
|
|
|
|
|
|
[rule.threat.tactic]
|
|
id = "TA0011"
|
|
name = "Command and Control"
|
|
reference = "https://attack.mitre.org/tactics/TA0011/"
|
|
|