ID | Technique | Tactic |
---|---|---|
T1190 | Exploit Public-Facing Application | Initial Access |
Detection: Cisco IOS XE Implant Access
Description
The following analytic identifies the potential exploitation of a vulnerability (CVE-2023-20198) in the Web User Interface of Cisco IOS XE software. It detects suspicious account creation and subsequent actions, including the deployment of a non-persistent implant configuration file. The detection leverages the Web datamodel, focusing on specific URL patterns and HTTP methods. This activity is significant as it indicates unauthorized administrative access, which can lead to full control of the device. If confirmed malicious, attackers could maintain privileged access, compromising the device's integrity and security.
Search
1
2| tstats count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url IN ("/webui/logoutconfirm.html?logon_hash=*") Web.http_method=POST Web.status=200 by Web.http_user_agent, Web.status Web.http_method, Web.url, Web.url_length, Web.src, Web.dest, sourcetype
3| `drop_dm_object_name("Web")`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `cisco_ios_xe_implant_access_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
Suricata | N/A | 'suricata' |
'suricata' |
N/A |
Macros Used
Name | Value |
---|---|
security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
cisco_ios_xe_implant_access_filter | search * |
cisco_ios_xe_implant_access_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
This detection requires the Web datamodel to be populated from a supported Technology Add-On like Splunk for Apache, Splunk for Nginx, or Splunk for Palo Alto.
Known False Positives
False positives may be present, restrict to Cisco IOS XE devices or perimeter appliances. Modify the analytic as needed based on hunting for successful exploitation of CVE-2023-20198.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
Possible exploitation of CVE-2023-20198 against $dest$ by $src$. | 81 | 90 | 90 |
References
-
https://blog.talosintelligence.com/active-exploitation-of-cisco-ios-xe-software/
-
https://github.com/vulncheck-oss/cisco-ios-xe-implant-scanner
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | suricata |
suricata |
Integration | ✅ Passing | Dataset | suricata |
suricata |
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
Source: GitHub | Version: 2