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 |
AeonDave