This analytic detects a suspicious process making a DNS query via known, abused text-paste web services, VoIP, instant messaging, and digital distribution platforms used to download external files. This technique is abused by adversaries, malware actors, and red teams to download a malicious file on the target host. This is a good TTP indicator for possible initial access techniques. A user will experience false positives if the following instant messaging is allowed or common applications like telegram or discord are allowed in the corporate network.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-01-18
- Author: Teoderick Contreras, Splunk
- ID: 3cf0dc36-484d-11ec-a6bc-acde48001122
Kill Chain Phase
1 2 3 4 5 `sysmon` EventCode=22 QueryName IN ("*pastebin*", "*discord*", "*telegram*", "*t.me*") process_name IN ("cmd.exe", "*powershell*", "pwsh.exe", "wscript.exe", "cscript.exe") | stats count min(_time) as firstTime max(_time) as lastTime by Image QueryName QueryStatus process_name QueryResults Computer | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `suspicious_process_dns_query_known_abuse_web_services_filter`
The SPL above uses the following Macros:
suspicious_process_dns_query_known_abuse_web_services_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
How To Implement
This detection relies on sysmon logs with the Event ID 22, DNS Query. We suggest you run this detection at least once a day over the last 14 days.
Known False Positives
Noise and false positive can be seen if the following instant messaging is allowed to use within corporate network. In this case, a filter is needed.
Associated Analytic story
|64.0||80||80||suspicious process $process_name$ has a dns query in $QueryName$ on $Computer$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 2