LoFP / be aware of potential false positives - legitimate uses of the /webauth_operation.php endpoint may cause benign activities to be flagged.the url in the analytic is specific to a successful attempt to exploit the vulnerability. review contents of the http body to determine if the request is malicious. if the request is benign, add the url to the whitelist or continue to monitor.

Techniques

• T1059
• T1105
• T1190

Sample rules

Juniper Networks Remote Code Execution Exploit Detection

• source: splunk
• technicques:
  • T1190
  • T1105
  • T1059

Description

The following analytic detects the exploitation of a remote code execution vulnerability in Juniper Networks devices. The vulnerability involves multiple steps, including uploading a malicious PHP file and an INI file to the target server, and then executing the PHP code by manipulating the PHP configuration via the uploaded INI file. The analytic specifically looks for requests to /webauth_operation.php?PHPRC=*, which are used to upload the files and execute the code, respectively. This behavior is worth identifying for a SOC because it indicates that an attacker is attempting to exploit the vulnerability to gain unauthorized access to the device and execute arbitrary code. If a true positive is found, it suggests that an attacker has successfully exploited the vulnerability and may have gained control over the device, leading to data theft, network compromise, or other damaging outcomes. Upon triage, review the request parameters and the response to determine if the exploitation was successful. Capture and inspect any relevant network traffic and server logs to identify the attack source. This approach helps analysts detect potential threats earlier and mitigate the risks.

Detection logic

| tstats count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url IN ("*/webauth_operation.php?PHPRC=*") Web.status=200 by Web.http_user_agent, Web.status Web.http_method, Web.url, Web.url_length, Web.src, Web.dest, sourcetype 
| `drop_dm_object_name("Web")` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `juniper_networks_remote_code_execution_exploit_detection_filter`