The following analytic identifies a suspicious registry modification of Windows max connection per server configuration. This particular technique has been observed in various threat actors, adversaries, and even in malware such as the Warzone (Ave Maria) RAT. By altering the max connection per server setting in the Windows registry, attackers can potentially increase the number of concurrent connections allowed to a remote server. This modification could be exploited for various malicious purposes, including facilitating distributed denial-of-service (DDoS) attacks or enabling more effective lateral movement within a compromised network.
- Type: Anomaly
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-07-26
- Author: Teoderick Contreras, Splunk
- ID: 064cd09f-1ff4-4823-97e0-45c2f5b087ec
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry where (Registry.registry_path= "*\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Internet Settings\\MaxConnectionsPerServer*" OR Registry.registry_path= "*\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Internet Settings\\MaxConnectionsPer1_0Server*") Registry.registry_value_data = "0x0000000a" by Registry.registry_key_name Registry.user Registry.registry_path Registry.registry_value_data Registry.action Registry.dest | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_modify_registry_maxconnectionperserver_filter`
The SPL above uses the following Macros:
windows_modify_registry_maxconnectionperserver_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 information on process that include the name of the process responsible for the changes from your endpoints into the
Endpoint datamodel in the
Registry node. Also make sure that this registry was included in your config files ex. sysmon config to be monitored.
Known False Positives
Administrators may enable or disable this feature that may cause some false positive.
Associated Analytic Story
|25.0||50||50||A registry modification in max connection per server configuration in $dest$|
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