Sigma rule: Office Application Initiated Network Connection To Non-Local IP

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-4712026d43ad, updated 2025-10-17T00:00:00.000Z.

Rule

Title
Office Application Initiated Network Connection To Non-Local IP
Status
test
Level
medium
Author
Christopher Peacock '@securepeacock', SCYTHE '@scythe_io', Florian Roth (Nextron Systems), Tim Shelton, Nasreddine Bencherchali (Nextron Systems)
Date
2021-11-10
Modified
2025-10-17
File
rules/windows/network_connection/net_connection_win_office_outbound_non_local_ip.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects an office application (Word, Excel, PowerPoint) that initiate a network connection to a non-private IP addresses.
This rule aims to detect traffic similar to one seen exploited in CVE-2021-42292.
This rule will require an initial baseline and tuning that is specific to your organization.

Log source

product
windows
category
network_connection

Detection

selection:
    Image|endswith:
        - '\excel.exe'
        - '\outlook.exe'
        - '\powerpnt.exe'
        - '\winword.exe'
        - '\wordview.exe'
    Initiated: 'true'
filter_main_local_ranges:
    DestinationIp|cidr:
        - '127.0.0.0/8'
        - '10.0.0.0/8'
        - '172.16.0.0/12'
        - '192.168.0.0/16'
        - '169.254.0.0/16'
        - '::1/128'  # IPv6 loopback
        - 'fe80::/10'  # IPv6 link-local addresses
        - 'fc00::/7'  # IPv6 private addresses
filter_main_msrange_generic:
    DestinationIp|cidr:
        - '2.16.56.0/23' # Akamai International B.V.
        - '2.17.248.0/21' # Akamai International B.V.
        - '13.107.240.0/21' # Microsoft Corporation
        - '20.184.0.0/13' # Microsoft Corporation
        - '23.61.224.0/20' # Akamai-AS
        - '20.192.0.0/10' # Microsoft Corporation
        - '23.72.0.0/13' # Akamai International B.V.
        - '23.3.88.0/22' # Akamai-AS
        - '23.216.132.0/22' # Akamai-AS
        - '40.76.0.0/14' # Microsoft Corporation
        - '51.10.0.0/15' # Microsoft Corporation
        - '51.103.0.0/16' # Microsoft Corporation
        - '51.104.0.0/15' # Microsoft Corporation
        - '51.142.136.0/22' # Microsoft Corporation - https://ipinfo.io/AS8075/51.140.0.0/14-51.142.136.0/22
        - '52.160.0.0/11' # Microsoft Corporation - https://ipinfo.io/AS8075/52.160.0.0/11
        - '95.101.96.0/21' # Akamai-As
        - '204.79.197.0/24' # Microsoft Corporation
filter_main_msrange_exchange_1:
    # Exchange Online
    # "urls": [
    #       "outlook.cloud.microsoft",
    #       "outlook.office.com",
    #       "outlook.office365.com"
    # ]
    DestinationIp|cidr:
        - '13.107.4.0/22'
        - '13.107.6.152/31'
        - '13.107.18.10/31'
        - '13.107.42.0/23'
        - '13.107.128.0/22'
        - '23.35.224.0/20'
        - '23.53.40.0/22'
        - '23.103.160.0/20'
        - '23.216.76.0/22'
        - '40.96.0.0/13'
        - '40.104.0.0/15'
        - '52.96.0.0/14'
        - '131.253.33.215/32'
        - '132.245.0.0/16'
        - '150.171.32.0/22'
        - '204.79.197.215/32'
        - '2603:1006::/40'
        - '2603:1016::/36'
        - '2603:1026::/36'
        - '2603:1036::/36'
        - '2603:1046::/36'
        - '2603:1056::/36'
        - '2620:1ec:4::152/128'
        - '2620:1ec:4::153/128'
        - '2620:1ec:c::10/128'
        - '2620:1ec:c::11/128'
        - '2620:1ec:d::10/128'
        - '2620:1ec:d::11/128'
        - '2620:1ec:8f0::/46'
        - '2620:1ec:900::/46'
        - '2620:1ec:a92::152/128'
        - '2620:1ec:a92::153/128'
    DestinationPort:
        - 80
        - 443
filter_main_msrange_exchange_2:
    # Exchange Online
    # "urls": [
    #       "outlook.office365.com",
    #       "smtp.office365.com"
    # ]
    DestinationIp|cidr:
        - '13.107.6.152/31'
        - '13.107.18.10/31'
        - '13.107.128.0/22'
        - '23.103.160.0/20'
        - '40.96.0.0/13'
        - '40.104.0.0/15'
        - '52.96.0.0/14'
        - '131.253.33.215/32'
        - '132.245.0.0/16'
        - '150.171.32.0/22'
        - '204.79.197.215/32'
        - '2603:1006::/40'
        - '2603:1016::/36'
        - '2603:1026::/36'
        - '2603:1036::/36'
        - '2603:1046::/36'
        - '2603:1056::/36'
        - '2620:1ec:4::152/128'
        - '2620:1ec:4::153/128'
        - '2620:1ec:c::10/128'
        - '2620:1ec:c::11/128'
        - '2620:1ec:d::10/128'
        - '2620:1ec:d::11/128'
        - '2620:1ec:8f0::/46'
        - '2620:1ec:900::/46'
        - '2620:1ec:a92::152/128'
        - '2620:1ec:a92::153/128'
    DestinationPort:
        - 143
        - 587
        - 993
        - 995
    Protocol: 'tcp'
filter_main_msrange_exchange_3:
    # Exchange Online
    # "urls": [
    #       "*.protection.outlook.com"
    #  ]
    DestinationIp|cidr:
        - '40.92.0.0/15'
        - '40.107.0.0/16'
        - '52.100.0.0/14'
        - '52.238.78.88/32'
        - '104.47.0.0/17'
        - '2a01:111:f400::/48'
        - '2a01:111:f403::/48'
    DestinationPort: 443
filter_main_msrange_exchange_4:
    # Exchange Online
    # "urls": [
    #       "*.mail.protection.outlook.com",
    #       "*.mx.microsoft"
    #  ]
    DestinationIp|cidr:
        - '40.92.0.0/15'
        - '40.107.0.0/16'
        - '52.100.0.0/14'
        - '52.238.78.88/32'
        - '104.47.0.0/17'
        - '2a01:111:f400::/48'
        - '2a01:111:f403::/48'
    DestinationPort: 25
filter_main_msrange_sharepoint_1:
    # SharePoint Online and OneDrive for Business",
    # "urls": [
    #       "*.sharepoint.com"
    # ]
    DestinationIp|cidr:
        - '13.107.136.0/22'
        - '40.108.128.0/17'
        - '52.104.0.0/14'
        - '104.146.128.0/17'
        - '150.171.40.0/22'
        - '2603:1061:1300::/40'
        - '2620:1ec:8f8::/46'
        - '2620:1ec:908::/46'
        - '2a01:111:f402::/48'
    DestinationPort:
        - 80
        - 443
    Protocol: 'tcp'
filter_main_msrange_office_1:
    # Microsoft 365 Common and Office Online",
    # "urls": [
    #       "*.officeapps.live.com",
    #       "*.online.office.com",
    #       "office.live.com",
    #       "office.com.akadns.net"
    # ],
    DestinationIp|cidr:
        - '13.107.6.171/32'
        - '13.107.18.15/32'
        - '13.107.140.6/32'
        - '20.64.0.0/10'
        - '52.108.0.0/14'
        - '52.244.37.168/32'
        - '2603:1006:1400::/40'
        - '2603:1016:2400::/40'
        - '2603:1026:2400::/40'
        - '2603:1036:2400::/40'
        - '2603:1046:1400::/40'
        - '2603:1056:1400::/40'
        - '2603:1063:2000::/38'
        - '2620:1ec:c::15/128'
        - '2620:1ec:8fc::6/128'
        - '2620:1ec:a92::171/128'
        - '2a01:111:f100:2000::a83e:3019/128'
        - '2a01:111:f100:2002::8975:2d79/128'
        - '2a01:111:f100:2002::8975:2da8/128'
        - '2a01:111:f100:7000::6fdd:6cd5/128'
        - '2a01:111:f100:a004::bfeb:88cf/128'
    DestinationPort:
        - 80
        - 443
    Protocol: 'tcp'
filter_main_msrange_office_2:
    # Microsoft 365 Common and Office Online
    # "urls": [
    #       "*.auth.microsoft.com",
    #       "*.msftidentity.com",
    #       "*.msidentity.com",
    #       "account.activedirectory.windowsazure.com",
    #       "accounts.accesscontrol.windows.net",
    #       "adminwebservice.microsoftonline.com",
    #       "api.passwordreset.microsoftonline.com",
    #       "autologon.microsoftazuread-sso.com",
    #       "becws.microsoftonline.com",
    #       "ccs.login.microsoftonline.com",
    #       "clientconfig.microsoftonline-p.net",
    #       "cloudapp.azure.com",
    #       "companymanager.microsoftonline.com",
    #       "device.login.microsoftonline.com",
    #       "graph.microsoft.com",
    #       "graph.windows.net",
    #       "login-us.microsoftonline.com",
    #       "login.microsoft.com",
    #       "login.microsoftonline-p.com",
    #       "login.microsoftonline.com",
    #       "login.windows.net",
    #       "logincert.microsoftonline.com",
    #       "loginex.microsoftonline.com",
    #       "nexus.microsoftonline-p.com",
    #       "passwordreset.microsoftonline.com",
    #       "provisioningapi.microsoftonline.com",
    #       "web.core.windows.net",
    # ]
    DestinationIp|cidr:
        - '172.128.0.0/10'
        - '20.20.32.0/19'
        - '20.103.156.88/32' # msn.com
        - '20.190.128.0/18'
        - '20.231.128.0/19'
        - '40.126.0.0/18'
        - '57.150.0.0/15'
        - '2603:1006:2000::/48'
        - '2603:1007:200::/48'
        - '2603:1016:1400::/48'
        - '2603:1017::/48'
        - '2603:1026:3000::/48'
        - '2603:1027:1::/48'
        - '2603:1036:3000::/48'
        - '2603:1037:1::/48'
        - '2603:1046:2000::/48'
        - '2603:1047:1::/48'
        - '2603:1056:2000::/48'
        - '2603:1057:2::/48'
    DestinationPort:
        - 80
        - 443
    Protocol: 'tcp'
filter_main_msrange_office_3:
    # Microsoft 365 Common and Office Online
    #  "urls": [
    #       "*.compliance.microsoft.com",
    #       "*.data.microsoft.com",
    #       "*.protection.office.com",
    #       "*.security.microsoft.com",
    #       "compliance.microsoft.com",
    #       "defender.microsoft.com",
    #       "protection.office.com",
    #       "security.microsoft.com",
    #       "teams.microsoft.com",
    #  ]
    DestinationIp|cidr:
        - '13.64.0.0/11'
        - '13.107.6.192/32'
        - '13.107.9.192/32'
        - '13.89.179.14/32'
        - '20.40.0.0/14'
        - '20.48.0.0/12'
        - '20.64.0.0/12'
        - '52.123.0.0/16'
        - '52.108.0.0/14'
        - '52.136.0.0/13'
        - '57.150.0.0/15'
        - '80.239.150.67/32' # Arelion Sweden AB
        - '2620:1ec:4::192/128'
        - '2620:1ec:a92::192/128'
    DestinationPort: 443
    Protocol: 'tcp'
filter_main_destination_host:
    DestinationHostname|endswith: '.deploy.static.akamaitechnologies.com'
    DestinationPort: 443
    Protocol: 'tcp'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

  • You may have to tune certain domains out that Excel may call out to, such as microsoft or other business use case domains.
  • Office documents commonly have templates that refer to external addresses, like "sharepoint.ourcompany.com" may have to be tuned.
  • It is highly recommended to baseline your activity and tune out common business use cases.

Tags

  • attack.execution
  • attack.t1203

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/network_connection/net_connection_win_office_outbound_non_local_ip.yml

Sources and licences

  • SigmaHQ

    "Office Application Initiated Network Connection To Non-Local IP" by Christopher Peacock '@securepeacock', SCYTHE '@scythe_io', Florian Roth (Nextron Systems), Tim Shelton, Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/network_connection/net_connection_win_office_outbound_non_local_ip.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Office Application Initiated Network Connection To Non-Local IP",
entity page, dataset version ref-4712026d43ad, updated 2025-10-17T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/75e33ce3-ae32-4dcc-9aa8-a2a3029d6f84 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 75e33ce3-ae32-4dcc-9aa8-a2a3029d6f84, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.