Detect DNS Server in CrowdStrike LogScale
Adversaries may compromise third-party DNS servers to support operations. By gaining control over DNS infrastructure, adversaries can alter DNS records to redirect organizational traffic, facilitate credential harvesting, or redirect users to adversary-controlled infrastructure mimicking legitimate services. This technique is used by threat actors including Sea Turtle and LAPSUS$, who modified NS records and DNS configurations to intercept traffic at scale. Unlike acquiring new DNS infrastructure (T1583.002), this involves compromising existing, trusted DNS servers — making detection harder due to the perceived legitimacy of the infrastructure.
MITRE ATT&CK
- Tactic
- Resource Development
- Technique
- T1584 Compromise Infrastructure
- Sub-technique
- T1584.002 DNS Server
- Canonical reference
- https://attack.mitre.org/techniques/T1584/002/
LogScale Detection Query
// Detection Part 1: Outbound DNS queries to non-authorized resolvers (Falcon NetworkConnectIP4)
#event_simpleName = "NetworkConnectIP4"
| RemotePort = 53
| RemoteAddressIP4 != /^10\.\d{1,3}\.\d{1,3}\.\d{1,3}$/
| RemoteAddressIP4 != /^172\.(1[6-9]|2[0-9]|3[01])\.\d{1,3}\.\d{1,3}$/
| RemoteAddressIP4 != /^192\.168\.\d{1,3}\.\d{1,3}$/
| RemoteAddressIP4 != /^127\.\d{1,3}\.\d{1,3}\.\d{1,3}$/
| RemoteAddressIP4 != "8.8.8.8"
| RemoteAddressIP4 != "8.8.4.4"
| RemoteAddressIP4 != "1.1.1.1"
| RemoteAddressIP4 != "1.0.0.1"
| RemoteAddressIP4 != "9.9.9.9"
| indicator := "Rogue DNS Server Query"
| rename(field=FileName, as=ProcessName)
| table(
columns=[_time, ComputerName, UserName, ProcessName, CommandLine,
LocalAddressIP4, RemoteAddressIP4, RemotePort, indicator],
limit=1000
)
// Detection Part 2: DNS registry config changes (Falcon RegGenericValueUpdate) — run separately or union
// #event_simpleName = "RegGenericValueUpdate"
// | RegObjectName = /(?i).*\\Services\\Tcpip\\Parameters.*/
// | RegValueName = /(?i)^(NameServer|DhcpNameServer|SearchList|DhcpDomain)$/
// | indicator := "DNS Registry Config Changed"
// | rename(field=FileName, as=ProcessName)
// | table(
// columns=[_time, ComputerName, UserName, ProcessName, CommandLine,
// RegObjectName, RegValueName, RegStringValue, indicator],
// limit=1000
// )
| sort(field=_time, order=desc)CrowdStrike LogScale (Falcon Query Language) detection for T1584.002 targeting Falcon sensor event types. Part 1 uses NetworkConnectIP4 events to detect port 53 outbound connections to non-RFC1918, non-authorized resolver IPs. Part 2 (provided as commented union block) uses RegGenericValueUpdate events to detect DNS configuration registry key modifications to Tcpip\Parameters DNS value names. Both parts should be deployed as separate saved searches or combined using LogScale union syntax depending on version capabilities.
Data Sources
Required Tables
False Positives & Tuning
- Endpoints running local DNS resolver software such as dnscrypt-proxy, Pi-hole (if installed on endpoint), or systemd-resolved in forwarding mode that make outbound port 53 connections to non-standard upstream resolvers as part of their normal DNS resolution chain — these will appear as rogue DNS connections from the resolver process
- CrowdStrike Falcon sensor's own DNS telemetry collection or CrowdStrike backend connectivity checks that make DNS queries to CrowdStrike infrastructure IPs may appear in NetworkConnectIP4 telemetry depending on sensor configuration and version
- Security testing tools, network scanners (Nessus, Qualys, Rapid7), and pentest frameworks that probe remote TCP/UDP port 53 during authorized network discovery scans will generate high-volume matches against the rogue DNS detection branch
Other platforms for T1584.002
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Configure Rogue DNS Server via Registry
Expected signal: Sysmon Event ID 13 (Registry Value Set): TargetObject containing 'Tcpip\Parameters\Interfaces' and RegistryValueName 'NameServer', with Details '127.0.0.1', Image=reg.exe. Security Event ID 4657 (if object access auditing is enabled for registry). The initiating process reg.exe is unusual for a NameServer modification — legitimate changes come from svchost.exe (DHCP client).
- Test 2Direct DNS Query to Rogue Resolver
Expected signal: Sysmon Event ID 3 (Network Connection): DestinationIp=8.8.8.8, DestinationPort=53, Image=nslookup.exe. Sysmon Event ID 22 (DNS Query): QueryName=microsoft.com, Image=nslookup.exe. If 8.8.8.8 is not in the authorized DNS list, the DeviceNetworkEvents alert fires.
- Test 3Modify DNS Server via PowerShell
Expected signal: Sysmon Event ID 1 (Process Create): Image=powershell.exe, CommandLine containing 'Set-DnsClientServerAddress' and 'ServerAddresses'. Sysmon Event ID 13 (Registry Value Set): TargetObject under Tcpip\Parameters\Interfaces with NameServer value changed, Image=powershell.exe. PowerShell ScriptBlock Logging Event ID 4104 with full command content.
- Test 4DNS Query to Multiple Non-Authorized Resolvers
Expected signal: Three separate Sysmon Event ID 3 (Network Connection) events: DestinationPort=53 to 8.8.8.8, 1.1.1.1, and 9.9.9.9 respectively, Image=nslookup.exe. Three Sysmon Event ID 22 (DNS Query) events for example.com. Sysmon Event ID 1 for cmd.exe and nslookup.exe process creations.
References (11)
- https://attack.mitre.org/techniques/T1584/002/
- https://www.fireeye.com/blog/threat-research/2019/01/global-dns-hijacking-campaign-dns-record-manipulation-at-scale.html
- https://www.crowdstrike.com/blog/widespread-dns-hijacking-activity-targets-multiple-sectors/
- https://blog.talosintelligence.com/2018/11/dnspionage-campaign-targets-middle-east.html
- https://blog.talosintelligence.com/2019/04/seaturtle.html
- https://blogs.cisco.com/security/talos/angler-domain-shadowing
- https://www.proofpoint.com/us/threat-insight/post/The-Shadow-Knows
- https://cybercx.com.au/blog/keys-to-the-saas-kingdom/
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-devicenetworkevents-table
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceregistryevents-table
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1584.002/T1584.002.md
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