Detect Gather Victim Network Information in Splunk
This detection identifies adversary reconnaissance activity targeting victim network information, including IP ranges, domain names, DNS records, network topology, and security appliance configurations. Because T1590 is a PRE-ATT&CK technique, direct detection within the victim environment is limited; however, second-order indicators are observable when adversaries deploy internal network enumeration tools post-compromise (as seen with Volt Typhoon, Indrik Spider, and HAFNIUM), attempt DNS zone transfers, execute WHOIS or DNS enumeration utilities, or run network discovery tools such as Lansweeper and Advanced IP Scanner. Detection focuses on process execution of known network reconnaissance binaries, DNS zone transfer attempts, and anomalous internal network topology queries that suggest an adversary mapping the environment for lateral movement or targeting.
MITRE ATT&CK
- Tactic
- Reconnaissance
- Technique
- T1590 Gather Victim Network Information
- Canonical reference
- https://attack.mitre.org/techniques/T1590/
SPL Detection Query
index=* (sourcetype="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" EventCode=1)
| eval CommandLower=lower(CommandLine)
| eval ImageLower=lower(Image)
| eval ReconCategory=case(
match(CommandLower, "nmap|masscan|zmap|fping|nbtscan|unicornscan"), "PortHostScanning",
match(CommandLower, "dnsrecon|dnsenum|fierce|axfr|zone.transfer|\.transfer"), "DNSEnumeration",
match(CommandLower, "lansweeper|advanced.port.scanner|angryip|netdiscover|advanced_port"), "NetworkDiscoveryTool",
match(CommandLower, "\/dclist|\/domain_trusts|\/trusted_domains|\/dsgetdc") AND match(ImageLower, "nltest"), "DomainTrustEnumeration",
match(ImageLower, "nmap\.exe|masscan\.exe|lansweeper\.exe|dnsrecon\.py|fierce\.py"), "KnownReconBinary",
true(), null())
| where isnotnull(ReconCategory)
| eval SuspicionScore=case(
ReconCategory="PortHostScanning", 90,
ReconCategory="DNSEnumeration", 85,
ReconCategory="NetworkDiscoveryTool", 80,
ReconCategory="DomainTrustEnumeration", 70,
ReconCategory="KnownReconBinary", 75,
50)
| eval ParentImageShort=mvindex(split(ParentImage, "\\"), -1)
| table _time, host, User, Image, CommandLine, ParentImage, ParentImageShort, ReconCategory, SuspicionScore
| sort -SuspicionScore -_timeDetects Sysmon process creation events matching known network reconnaissance binaries and command-line patterns including port scanners, DNS zone transfer attempts, DNS enumeration tools, and domain trust queries via nltest. Scores each finding by recon category to surface high-confidence indicators first.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Network administrators running legitimate scans using nmap, masscan, or equivalent tools during maintenance windows
- Lansweeper, SolarWinds, or other CMDB/network management platforms performing scheduled network discovery
- DNS replication between authoritative nameservers generating AXFR traffic visible in process logs
- Penetration test engagements where the security team is running authorized reconnaissance tools
- Automated IT asset discovery agents that use port scanning or DNS queries as part of normal inventory workflows
Other platforms for T1590
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 1Nmap Internal Subnet Port Scan
Expected signal: Sysmon EventCode 1 (process create) with Image=nmap.exe, CommandLine containing the subnet range. Sysmon EventCode 3 (network connect) showing connections from nmap.exe to multiple internal IPs on specified ports. DeviceProcessEvents and DeviceNetworkEvents telemetry in MDE.
- Test 2DNS Zone Transfer Attempt via nslookup
Expected signal: Sysmon EventCode 1 with Image=nslookup.exe, CommandLine containing 'AXFR' and the target domain. Windows DNS debug log (if enabled) will show an AXFR request from the client IP. DeviceProcessEvents in MDE captures the command line.
- Test 3Domain Trust Enumeration via nltest
Expected signal: Sysmon EventCode 1 (process create) for each nltest invocation with the respective flags in CommandLine. SecurityEvent EventID 4688 if process command line auditing is enabled via GPO. DeviceProcessEvents in MDE with full command line captured.
- Test 4Internal Network Discovery with Advanced IP Scanner
Expected signal: DeviceFileEvents showing advanced_ip_scanner.exe created in C:\Temp. Sysmon EventCode 11 (file create) for the binary. Process creation event for advanced_ip_scanner.exe. Network connection events to multiple internal IPs during scan. DeviceNetworkEvents in MDE showing mass internal connections.
References (5)
- https://attack.mitre.org/techniques/T1590/
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-038a
- https://www.volexity.com/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerabilities/
- https://www.microsoft.com/en-us/security/blog/2023/05/24/volt-typhoon-targets-us-critical-infrastructure-with-living-off-the-land-techniques/
- https://www.secureworks.com/research/indrik-spider
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