LoFP LoFP / false positives in pdf file opened pdf viewer having legitimate url link, however filter as needed.

Techniques

Sample rules

Description

This analytic is developed to detect suspicious pdf viewer processes that have a browser application child processes. This event was seen in a pdf spear phishing attachment containing a malicious URL link to download the actual payload. When a user clicks the malicious link the pdf viewer application will execute a process of the host default browser to connect to the malicious site. This anomaly detection can be a good indicator that a possible pdf file has a link executed by a user. The pdf viewer and browser list in this detection is still in progress, add the common browser and pdf viewer you use in opening pdf in your network.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name  IN ("AcroRd32.exe", "FoxitPDFReader.exe") Processes.process_name IN ("firefox.exe", "chrome.exe", "iexplore.exe") by Processes.user Processes.parent_process_name Processes.process_name  Processes.parent_process Processes.process Processes.process_id Processes.dest 
|`drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_phishing_pdf_file_executes_url_link_filter`