IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
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: 5m
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: 102
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")]
Framework: 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/