aeondave/testssl

testssl.sh

TLS/SSL testing script — protocols, ciphers, vulnerabilities, certificates.

Quick Start

# Full scan (all checks)
testssl.sh https://target.com

# Specific port
testssl.sh target.com:8443

# STARTTLS (mail server)
testssl.sh --starttls smtp mail.target.com:25

Core Flags

| Flag | Purpose | |------|---------| | -p | Check protocols (SSLv2/3, TLS 1.0-1.3) | | -s | List cipher suites (preferred + supported) | | -f | Check forward secrecy | | -h | Check HSTS / HPKP | | -U | Test all vulnerabilities | | -E | List cipher suites per protocol | | -B | Heartbleed (OpenSSL vulnerability) | | --beast | BEAST attack check | | --breach | BREACH check | | --crime | CRIME check | | --lucky13 | Lucky13 timing attack | | --poodle | POODLE (SSLv3) | | --sweet32 | Birthday attacks on 64-bit block ciphers | | --logjam | Logjam (DH key exchange weakness) | | --drown | DROWN attack (SSLv2 overlap) | | --ticketbleed | Ticketbleed (F5 vulnerability) | | --robot | ROBOT attack | | --tls-fallback | TLS_FALLBACK_SCSV check | | -e | List all supported ciphers | | --protocols | List supported protocols only | | --server-defaults | Server defaults (cert, session, etc.) | | --server-preference | Server cipher preference | | --client-simulation | Simulate handshake with common clients | | --starttls <proto> | STARTTLS: smtp / pop3 / imap / ftp / xmpp / ldap | | --mx | Test all MX records of a domain (mail servers) | | --file <file> | Batch mode — one target per line | | --mode parallel | Run batch in parallel (use with --file) | | --outprefix <str> | Prefix for all output files in batch mode | | --append | Append to existing output file | | --ip <ip> | Force specific IP for SNI hosts | | --proxy <host:port> | SOCKS5/HTTP proxy | | --sneaky | Sneaky mode (minimal headers) | | --ids-friendly | Avoid IDS trigger patterns | | -t <n> | Timeout per connection | | --connect-timeout <n> | Connection timeout | | --openssl <path> | Specify OpenSSL binary to use | | -oJ <file> | JSON output | | -oC <file> | CSV output | | -oH <file> | HTML output | | -oA <file> | All output formats (adds extensions) | | --color <0-3> | Color output level | | --quiet | Minimal output | | --warnings batch | Batch mode (no interactive prompts) | | --parallel | Parallel testing (faster, less reliable) | | --nodns <min> | Skip DNS reverse lookups |

Vulnerability Checks (-U runs all)

| Flag | Vulnerability | Impact | |------|--------------|--------| | --heartbleed | Heartbleed (CVE-2014-0160) | Memory leak → private key | | --ccs | CCS Injection (CVE-2014-0224) | MITM | | --ticketbleed | Ticketbleed (CVE-2016-9244) | Memory leak | | --robot | ROBOT (RSA PKCS#1 oracle) | RSA key recovery | | --breach | BREACH | HTTP compression info leak | | --crime | CRIME | TLS compression info leak | | --beast | BEAST | CBC mode attack (TLS 1.0) | | --poodle | POODLE | SSLv3 CBC attack | | --sweet32 | Sweet32 | 3DES birthday attack | | --logjam | Logjam | DH 512/1024-bit export weakness | | --drown | DROWN | SSLv2 cross-protocol attack | | --lucky13 | Lucky13 | CBC timing attack | | --tls-fallback | Downgrade fallback | Missing SCSV | | --freak | FREAK | Export RSA key exchange | | --rc4 | RC4 biases | Statistical attacks |

# Individual vuln flags (short form):
# -H heartbleed  -I CCS  -T ticketbleed  --BB ROBOT  -R renegotiation
# -C CRIME  -B BREACH  -O POODLE  -Z fallback  -W SWEET32
# -F FREAK  -D DROWN  -J LOGJAM  -A BEAST  -L LUCKY13  -4 RC4

Protocol & Cipher Assessment

# Protocol support check
testssl.sh -p target.com
# Look for: SSLv2 (critical), SSLv3 (critical), TLS 1.0/1.1 (warn)

# Cipher suites
testssl.sh -s target.com
# Look for: NULL, EXPORT, DES, RC4, 3DES (all bad)
# Want: AESGCM, CHACHA20, ECDHE (good)

# Check for forward secrecy (PFS)
testssl.sh -f target.com
# ECDHE/DHE = PFS available; RSA key exchange = no PFS

# Full cipher enumeration
testssl.sh -E target.com

Common Workflows

# Full assessment with all checks
testssl.sh -U -p -s -h -f --server-defaults target.com

# Quick vuln check only (fast)
testssl.sh -U --quiet target.com

# STARTTLS mail server
testssl.sh --starttls smtp mail.target.com:587
testssl.sh --starttls imap mail.target.com:143

# JSON output for reporting
testssl.sh --jsonfile report.json -U target.com

# HTML report
testssl.sh -oH report.html -U -p -s target.com

# All formats at once
testssl.sh -oA report -U -p -s -f target.com
# Creates: report.json, report.csv, report.html

# Client simulation (browser compatibility)
testssl.sh --client-simulation target.com

# Batch scan with built-in file mode (one target per line):
# targets.txt can contain: host:port, -t smtp host:587, etc.
testssl.sh --file targets.txt --warnings batch -U --quiet

# Parallel batch scan (built-in):
testssl.sh --file targets.txt --mode parallel --warnings batch \
    -oA pentest-$(date +%Y%m%d)  # creates .json .csv .html per target

# Test all mail servers (MX records) for domain:
testssl.sh --mx example.com

# Stealth / IDS-evasion mode:
testssl.sh --sneaky --ids-friendly --nodns min -U target.com

Key Findings for Reports

| Finding | Severity | Recommendation | |---------|----------|---------------| | SSLv2 enabled | Critical | Disable immediately | | SSLv3 enabled | Critical | Disable (POODLE) | | TLS 1.0 enabled | Medium/High | Disable if possible | | Heartbleed | Critical | Patch OpenSSL | | ROBOT | High | Disable RSA key exchange | | NULL ciphers | Critical | Remove | | EXPORT ciphers | Critical | Remove | | RC4 ciphers | High | Remove | | 3DES (Sweet32) | Medium | Remove | | DH < 2048-bit | Medium | Use 2048+ bit DH | | Self-signed cert | Medium | Replace with trusted CA | | Expired cert | High | Renew certificate | | No HSTS | Low/Medium | Add Strict-Transport-Security | | No PFS | Medium | Enable ECDHE ciphers | | SHA1 certificate | Medium | Replace with SHA256+ |

Output Parsing

# Extract findings from JSON
cat report.json | jq '.[] | select(.severity != "OK" and .severity != "INFO") | {id: .id, severity: .severity, finding: .finding}'

# Count by severity
cat report.json | jq '[.[] | .severity] | group_by(.) | map({severity: .[0], count: length})'

# Extract certificate info
cat report.json | jq '.[] | select(.id | startswith("cert")) | {id: .id, finding: .finding}'

# Find critical/high findings only
cat report.json | jq '.[] | select(.severity == "CRITICAL" or .severity == "HIGH") | {id, finding}'

Resources

| File | When to load | |------|--------------| | references/tls-hardening.md | TLS configuration best practices, cipher suite recommendations, HSTS setup |