What it is
File-sharing ports: SMB, NFS, FTP, rsync.
Why it is risky
Internet exposure is a conduit for ransomware spread and data leakage; SMB is a perennial worm target (EternalBlue-class).
What to do
Restrict to internal networks / VPN, apply least-privilege shares and patches, and replace FTP with SFTP.
Is it listening on your server?
Linux
ss -ltnp 'sport = :21'Known vulnerabilities in FTP
| CVE | Title | CVSS | Exploited | EPSS | Published |
|---|---|---|---|---|---|
| CVE-2011-2523 | vsftpd 2.3.4 downloaded between 20110630 and 20110703 contains a backdoor which opens a shell on port 6200/tcp... | 9.8 | — | 2019-11-27 | |
| CVE-2021-30047 | VSFTPD 3.0.3 allows attackers to cause a denial of service due to limited number of connections allowed. | 7.5 | — | 2023-08-22 | |
| CVE-2021-3618 | ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing differen... | 7.4 | 2.0% | 2022-03-23 | |
| CVE-2015-1419 | Unspecified vulnerability in vsftpd 3.0.2 and earlier allows remote attackers to bypass access restrictions vi... | 5.0 | — | 2015-01-28 | |
| CVE-2011-0762 | The vsf_filename_passes_filter function in ls.c in vsftpd before 2.3.3 allows remote authenticated users to ca... | 4.0 | — | 2011-03-02 |
Track these versions on your own servers
InfraGuard collects installed software versions from every server and flags the ones with known vulnerabilities. Self-hosted — nothing leaves your network.