Virus/Spyware “Port Numbers” — What’s Real, What’s Not, and What to Watch
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Key point: There is NO complete “list of all virus and spyware port numbers”
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There isn’t a definitive, comprehensive list of ports used by “all viruses and spyware” because:
– Malware authors can use ANY port (1–65535), and frequently change ports.
– Many modern threats use normal web traffic (HTTPS/TLS) on port 443 to blend in.
– Malware can tunnel through DNS (53), email protocols, cloud APIs, or custom encrypted channels.
– Ports alone do not tell you if traffic is malicious; context and behavior matter.

If someone claims they have “all virus/spyware ports,” treat that as misleading.

What defenders SHOULD do instead
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– Use endpoint protection/EDR and network security monitoring.
– Inspect and correlate:
– destination domain/IP reputation
– TLS fingerprints (if available)
– unusual beaconing patterns (regular intervals)
– unusual processes initiating network connections
– data exfiltration patterns (large outbound transfers, odd hours)
– Block known bad IPs/domains and use threat intel feeds.
– Use DNS security (block newly registered domains, lookalikes, suspicious TLDs).
– Segment networks and restrict outbound traffic where feasible (egress filtering).

Commonly abused ports (NOT “virus ports”) — high-level watch list
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These are legitimate ports that malware and spyware sometimes abuse because they are
commonly allowed or provide remote access. Monitoring them can help, but they are NOT
inherently malicious.

Web / common outbound
– 80 HTTP
– 443 HTTPS (most common for stealthy command-and-control and exfiltration)
– 8080 Alternate HTTP (proxies/apps)
– 8443 Alternate HTTPS (apps/management)

Name resolution / tunneling
– 53 DNS (sometimes abused for DNS tunneling)

Email-related (phishing + exfil sometimes piggybacks)
– 25 SMTP
– 465 SMTPS
– 587 SMTP submission
– 993 IMAPS
– 995 POP3S

Remote access / lateral movement targets (especially in Windows environments)
– 3389 RDP (should not be exposed to the internet)
– 445 SMB (block from internet; common worm/ransomware target)
– 135 RPC (Windows)
– 139 NetBIOS (legacy Windows)
– 5985 WinRM (HTTP)
– 5986 WinRM (HTTPS)

Legacy / insecure protocols (reduce/disable where possible)
– 21 FTP
– 23 Telnet
– 110 POP3
– 143 IMAP

Database/management ports (high value if exposed)
– 22 SSH
– 1433 Microsoft SQL Server
– 3306 MySQL
– 5432 PostgreSQL
– 27017 MongoDB
– 6379 Redis

Important cautions
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– Seeing traffic on any of the ports above does NOT mean “virus.”
– Conversely, malware can use “normal” ports (especially 443) and appear benign.
– Good detection focuses on who is talking to what, how often, and from which process.

Practical home-PC guidance
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– Keep Windows and browsers updated.
– Use Microsoft Defender (or reputable AV) with real-time protection.
– Avoid exposing RDP (3389) to the internet.
– Check your router for unknown port-forwards; disable UPnP if you don’t need it.
– If you suspect spyware:
– run a full antivirus scan + an offline scan
– review installed apps and browser extensions
– change passwords from a clean device, enable MFA
– consider a clean reinstall for high confidence