nslookup.exe

by Microsoft
Operating Systemmedium risk

Sources: 300M+ executions observed in the wild.

Summary

NSLookup (nslookup.exe) is a command-line tool for querying DNS name servers. It can look up IP addresses, MX records, NS records, and other DNS information. It is the primary built-in DNS diagnostic tool on Windows.

nslookup.exe is the 40th most commonly executed Windows program in EchoTrail's dataset, observed 913,162 times across enterprise environments. It typically runs from C:\Windows\System32 and it is most often launched by cmd.exe.

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40th
most commonly executed Windows program
913,162
observed endpoint executions

Behavior

Top Paths

  • C:\Windows\System32100%
  • C:\Windows\SysWOW64<0.01%

Top Hashes (SHA256)

  • 13c829643ef23ccbdc3675f1b015de74e8d3068b6ba871111ead7dcc025a558a97.73%
  • 24553bfab13871faf3ee6f1f8efecc5d25368a706a42ca35319228d3547418fa0.57%
  • 54daf167f8dbe7fe0f23b37a600bd8d9d16b756d3b83f0804b5037cbbe895eb60.52%
  • 0a8082a6d4db367b7b54d1cd682d693b6685758a0e77c27e0d62d36553a5f0a60.42%
  • 55ab032d256adbe3fde40cf90fe83ba5eab591e04ad720161ed8e6ef059ca7470.27%
  • 5b3e823a803bc6c3def556789d72b1aa48cc5668473a9e28addb00c728cee78f0.17%
  • de48fe357a0b4de5785501f791f8ecb3c0411f18738d6268c6f3a5920d8f30520.17%
  • 4a3e0efaf2ca9652808799fede09eb2b397d2e751993843fa659c00bb96596550.05%
  • e51bd36e0a381f7fd369f59d547e277ff2c8ab6d5e79b4add205a714e5d5daea0.05%
  • ed7c553ef847d0e6b42969d56d84ecda77d4770131f70661fd430c34d2bccb940.02%

Process Ancestry

Top Grandparents

Top Parents

Top Children

Security Analysis

What does nslookup.exe normally do?

Located in C:\Windows\System32. Predominantly launched by cmd.exe (97%) and monitoring agents (QualysAgent). Spawns conhost.exe. Used for DNS troubleshooting and domain lookups.

When is nslookup.exe suspicious?

Used as part of a discovery sequence with other recon tools. Lookups of known C2 domains or infrastructure. High-frequency DNS lookups from a scripted context. Launched by unusual parents (wmiprvse.exe, w3wp.exe). Data exfiltration via DNS — large volumes of nslookup queries encoding data in subdomains.

How do attackers abuse nslookup.exe?

DNS reconnaissance: attackers use nslookup to resolve internal hostnames, domain controllers, mail servers, and other infrastructure targets. DNS data exfiltration: in advanced attacks, nslookup can be used to send data via DNS queries by encoding it in subdomain labels. DNS C2: resolving C2 domains to get updated IP addresses or encoded commands via DNS TXT records.

Detection guidance

Medium-confidence: nslookup as part of a reconnaissance sequence. High volumes of nslookup queries from a single host in a short time window. nslookup queries for known-malicious domains. DNS exfiltration patterns: queries with unusually long subdomain labels or high query volumes to a single domain. Correlate with DNS query logs for full visibility.

False positive notes

Very common in monitoring and troubleshooting. QualysAgent and similar tools run nslookup regularly. System administrators use nslookup routinely for DNS debugging.

MITRE ATT&CK techniques

Related Processes

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