This documentation contains work-in-progress information for future Elastic Stack and Cloud releases. Use the version selector to view supported release docs. It also contains some Elastic Cloud serverless information. Check out our serverless docs for more details.
Unusual Network Connection via DllHost
editUnusual Network Connection via DllHost
editIdentifies unusual instances of dllhost.exe making outbound network connections. This may indicate adversarial Command and Control activity.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
Severity: medium
Risk score: 47
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
- https://www.microsoft.com/security/blog/2021/05/27/new-sophisticated-email-based-attack-from-nobelium/
- https://www.volexity.com/blog/2021/05/27/suspected-apt29-operation-launches-election-fraud-themed-phishing-campaigns/
- https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
Version: 101 (version history)
Added (Elastic Stack release): 7.14.0
Last modified (Elastic Stack release): 8.5.0
Rule authors: Elastic
Rule license: Elastic License v2
Rule query
editsequence by host.id, process.entity_id with maxspan=1m [process where event.type == "start" and process.name : "dllhost.exe" and process.args_count == 1] [network where process.name : "dllhost.exe" and not cidrmatch(destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29", "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24", "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10", "192.175.48.0/24", "198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10", "FF00::/8")]
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: System Binary Proxy Execution
- ID: T1218
- Reference URL: https://attack.mitre.org/techniques/T1218/
Rule version history
edit- Version 101 (8.5.0 release)
-
-
Updated query, changed from:
sequence by host.id, process.entity_id with maxspan=1m [process where event.type in ("start", "process_started") and process.name : "dllhost.exe" and process.args_count == 1] [network where process.name : "dllhost.exe" and not cidrmatch(destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29", "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24", "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10", "192.175.48.0/24", "198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10", "FF00::/8")]
-
- Version 4 (8.4.0 release)
-
- Formatting only
- Version 2 (8.2.0 release)
-
- Formatting only