Microsoft Sync Center Suspicious Network Connections

Hunt Hypothesis

Detects suspicious connections from Microsoft Sync Center to non-private IPs.

Detection Rule

Sigma (Original)

title: Microsoft Sync Center Suspicious Network Connections
id: 9f2cc74d-78af-4eb2-bb64-9cd1d292b87b
status: test
description: Detects suspicious connections from Microsoft Sync Center to non-private IPs.
references:
    - https://redcanary.com/blog/intelligence-insights-november-2021/
author: elhoim
date: 2022-04-28
modified: 2024-03-12
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055
    - attack.t1218
    - attack.execution
logsource:
    product: windows
    category: network_connection
detection:
    selection:
        Image|endswith: '\mobsync.exe'
    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
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium

KQL (Azure Sentinel)

imNetworkSession
| where (SrcProcessName endswith "\\mobsync.exe" or DstProcessName endswith "\\mobsync.exe") and (not((ipv4_is_in_range(DstIpAddr, "127.0.0.0/8") or ipv4_is_in_range(DstIpAddr, "10.0.0.0/8") or ipv4_is_in_range(DstIpAddr, "172.16.0.0/12") or ipv4_is_in_range(DstIpAddr, "192.168.0.0/16") or ipv4_is_in_range(DstIpAddr, "169.254.0.0/16") or ipv4_is_in_range(DstIpAddr, "::1/128") or ipv4_is_in_range(DstIpAddr, "fe80::/10") or ipv4_is_in_range(DstIpAddr, "fc00::/7"))))

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Privilege Escalation
• Tactic: Execution
• Technique: T1055 — T1055
• Technique: T1218 — T1218

References

• https://redcanary.com/blog/intelligence-insights-november-2021/
• SigmaHQ Rule