The following analytic leverages Event IDs 5140 or 5145 to identify a source computer accessing windows administrative shares (C$, Admin$ and IPC$ ) across a large number remote endpoints. Specifically, the logic will trigger when a source endpoint accesses administrative shares across 30 or more target computers within a 5 minute timespan. This behavior could represent an adversary who is enumerating network shares across an Active Directory environment in the search for sensitive files, a common technique leveraged by red teamers and threat actors. As environments differ across organizations, security teams should customize the thresholds of this detection as needed.
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2023-03-23
- Author: Mauricio Velazco, Splunk
- ID: d92f2d95-05fb-48a7-910f-4d3d61ab8655
Kill Chain Phase
- CIS 10
1 2 3 4 5 `wineventlog_security` EventCode=5140 OR EventCode=5145 (ShareName="\\\\*\\ADMIN$" OR ShareName="\\\\*\\IPC$" OR ShareName="\\\\*\\C$") | bucket span=5m _time | stats dc(Computer) AS unique_targets values(Computer) as host_targets values(ShareName) as shares by _time, IpAddress, SubjectUserName, EventCode | where unique_targets > 30 | `windows_administrative_shares_accessed_on_multiple_hosts_filter`
The SPL above uses the following Macros:
windows_administrative_shares_accessed_on_multiple_hosts_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To successfully implement this search, you need to be ingesting file share events. The Advanced Security Audit policy setting
Audit Detailed File Share or
Audit File Share within
Object Access need to be enabled.
Known False Positives
An single endpoint accessing windows administrative shares across a large number of endpoints is not common behavior. Possible false positive scenarios include but are not limited to vulnerability scanners, administration systems and missconfigured systems.
Associated Analytic Story
|56.0||70||80||$IpAddress$ accessed the IPC share on more than 30 endpoints in a timespan of 5 minutes.|
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: 1