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thumbtack.com

Name: thumbtack.com Email Security Posture Assessment
Creator: RacterMX

Posture Score: 70/100

Scanned May 8, 2026 at 5:24 PM UTC

Identity

Attack Surface

Reputation

Identity Findings

Open recursion on nameserver: ns-291.awsdns-36.com

The nameserver ns-291.awsdns-36.com allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.

💡 Disable recursion on ns-291.awsdns-36.com or restrict it to trusted networks only.

critical

Weak DKIM RSA key (~1296 bits) for selector 'default'

RSA keys shorter than 2048 bits are considered weak. Current key is approximately 1296 bits.

💡 Generate a new 2048-bit (or larger) RSA key pair and update the DKIM record.

high

Weak DKIM RSA key (~1296 bits) for selector 'google'

RSA keys shorter than 2048 bits are considered weak. Current key is approximately 1296 bits.

💡 Generate a new 2048-bit (or larger) RSA key pair and update the DKIM record.

high

Weak DKIM RSA key (~1296 bits) for selector 's2'

RSA keys shorter than 2048 bits are considered weak. Current key is approximately 1296 bits.

💡 Generate a new 2048-bit (or larger) RSA key pair and update the DKIM record.

high

Weak DKIM RSA key (~1296 bits) for selector 'mandrill'

RSA keys shorter than 2048 bits are considered weak. Current key is approximately 1296 bits.

💡 Generate a new 2048-bit (or larger) RSA key pair and update the DKIM record.

high

No MTA-STS record found

Without MTA-STS, mail transport encryption cannot be enforced and is vulnerable to downgrade attacks.

💡 Publish a _mta-sts TXT record and host a policy file at https://mta-sts.thumbtack.com/.well-known/mta-sts.txt

medium

STARTTLS without MTA-STS or DANE protection

STARTTLS alone is vulnerable to downgrade attacks. Neither MTA-STS nor DANE is configured to enforce encryption.

💡 Deploy MTA-STS and/or DANE to protect against STARTTLS stripping attacks.

medium

No CAA records found

No CAA records are configured. Any certificate authority can issue certificates for this domain.

💡 Add CAA records to restrict certificate issuance. Example: 0 issue "letsencrypt.org"

medium

No TLS-RPT record found

Without TLS-RPT, you will not receive reports about TLS negotiation failures.

💡 Publish a _smtp._tls TXT record (e.g. "v=TLSRPTv1; rua=mailto:tls-reports@thumbtack.com").

low

Slow DNS response from ns-291.awsdns-36.com: 2082.4ms

The nameserver ns-291.awsdns-36.com responded in 2082.4ms, exceeding the 500ms threshold.

💡 Investigate network latency or performance issues on ns-291.awsdns-36.com.

low

Very low TTL on A records: 60s

4 A records have a TTL of 60s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

Very low TTL on TXT records: 271s

25 TXT records have a TTL of 271s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

Very low TTL on SPF record: 271s

The SPF record has a TTL of 271s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

NS TTL mismatch between parent and authoritative zone

The NS record TTL in the parent zone (~7171s) differs significantly from the authoritative zone (~172800s).

💡 Align NS record TTLs between the parent zone delegation and the authoritative zone.

low

SPF record is valid

The SPF record is properly configured with valid syntax and within lookup limits.

pass

DKIM cryptographic configuration is compliant

No RFC 8301 compliance issues detected in DKIM key configuration.

pass

No deprecated DMARCbis tags present

The DMARC record does not use any tags deprecated in DMARCbis (pct, rf, ri).

pass

BIMI record is valid

BIMI is properly configured with a valid logo and DMARC enforcement.

pass

ARC support likely available

MX server software appears to support ARC headers for authentication preservation.

pass

SMTP security checks passed

No open relay, VRFY/EXPN, or banner disclosure issues detected.

pass

SMTP RFC 5321 compliance checks passed

The mail server accepts postmaster@ and abuse@ and uses a valid FQDN in EHLO.

pass

IPv6 readiness is good

IPv6 records are present and properly configured.

pass

DKIM2 not detected

No DKIM key record with v=2 was found across common selectors. DKIM2 is an emerging standard and not yet widely deployed.

informational

DMARC alignment: adkim=r, aspf=r

DKIM alignment is relaxed, SPF alignment is relaxed.

informational

DMARCbis np tag absent

The DMARC record does not include the np (non-existent subdomain policy) tag. Consider adding np=reject to protect non-existent subdomains under DMARCbis.

informational

DMARCbis psd tag absent

The DMARC record does not include the psd (public suffix domain) indicator. Consider adding psd=n to explicitly identify this as an organizational domain.

informational

Shared/free email hosting detected: aspmx.l.google.com

The MX record points to a known shared or free email hosting provider.

informational

Shared/free email hosting detected: alt3.aspmx.l.google.com

The MX record points to a known shared or free email hosting provider.

informational

Shared/free email hosting detected: alt4.aspmx.l.google.com

The MX record points to a known shared or free email hosting provider.

informational

Shared/free email hosting detected: alt1.aspmx.l.google.com

The MX record points to a known shared or free email hosting provider.

informational

Shared/free email hosting detected: alt2.aspmx.l.google.com

The MX record points to a known shared or free email hosting provider.

informational

No DANE/TLSA records found

DANE is not configured for any MX server. This is optional but provides strong certificate binding.

informational

Open mail ports on aspmx.l.google.com

Detected open mail-related ports: 25

informational

RFC 8058 one-click unsubscribe assessment

DKIM signing is configured. RFC 8058 compliance depends on List-Unsubscribe and List-Unsubscribe-Post headers being included in outbound messages and DKIM signatures.

informational

MX IP network diversity

MX IPs span 5 different /16 networks, providing good diversity.

informational

SOA record parameters

Serial: 1, Refresh: 7200s, Retry: 900s, Expire: 1209600s, Min TTL: 86400s

informational

Attack Surface Findings

DNS ANY query returns 38 record(s)

The DNS server responds to ANY queries with 38 record(s), creating significant DNS amplification risk.

💡 Configure the DNS server to refuse or minimize ANY query responses per RFC 8482.

medium

Domain enumerability: medium

The domain has moderate enumerability. CT logs and DNS records reveal significant information about the domain structure.

💡 Restrict zone transfers, use NSEC3 instead of NSEC, consider wildcard certificates to reduce CT log exposure, and implement rate limiting on DNS queries.

medium

DNSSEC is not enabled

No DNSKEY or DS records were found. DNS responses are not cryptographically authenticated.

💡 Enable DNSSEC by generating DNSKEY records and publishing DS records at the registrar.

medium

No internal information leakage detected

No non-routable IP addresses or internal references were found in public DNS records.

pass

No email autodiscovery endpoints detected

No Microsoft Autodiscover, Mozilla Autoconfig, or email SRV records were found.

pass

7 subdomain(s) discovered for thumbtack.com

Subdomains were enumerated via Certificate Transparency logs, DNS wordlist brute-forcing, and DNS record analysis.

informational

0 certificate(s) found in CT logs

Certificate Transparency logs contain 0 certificate(s) for thumbtack.com and its subdomains. Each certificate reveals subdomain names.

informational

Reputation Findings

Missing domain locks: clientDeleteProhibited

Domain thumbtack.com is missing protective locks: clientDeleteProhibited.

💡 Enable clientTransferProhibited and clientDeleteProhibited locks through your registrar to prevent unauthorized transfers or deletions.

high

Missing Strict-Transport-Security on thumbtack.com

The Strict-Transport-Security header is not set on https://thumbtack.com.

💡 Add the Strict-Transport-Security header with a max-age of at least 31536000 (1 year) and include the includeSubDomains directive.

medium

Missing security.txt

No security.txt found at https://thumbtack.com/.well-known/security.txt.

💡 Create a /.well-known/security.txt file per RFC 9116 with Contact, Expires, and optionally Encryption and Policy fields.

low

TLS certificate valid for 160 days

Certificate for thumbtack.com expires on 2026-10-15.

pass

Certificate issued by Amazon RSA 2048 M01

The certificate for thumbtack.com is issued by a third-party CA.

pass

Signature algorithm: rsa-sha256

The certificate for thumbtack.com uses an acceptable signature algorithm.

pass

RSA key: 2048 bits

The certificate for thumbtack.com uses an adequate RSA key of 2048 bits.

pass

SCTs present in certificate

The certificate for thumbtack.com contains Signed Certificate Timestamps.

pass

No weak ciphers detected

No known weak cipher suites detected on thumbtack.com.

pass

Domain valid for 175 days

Domain thumbtack.com expires on 2026-10-31.

pass

Google Safe Browsing DNS check — no flag detected

DNS-based Safe Browsing lookup returned no results. Full verification requires the Google Safe Browsing API key.

informational

Abuse contact lookup failed

Could not query abuse contact information.

informational

PhishTank — API key required

PhishTank phishing database check requires an API key.

informational

Sender Score — API key required

Sender Score reputation check requires an API key.

informational

Cisco Talos — API key required

Cisco Talos IP reputation check requires an API key.

informational

Could not connect to webmail.thumbtack.com

HTTPS request to https://webmail.thumbtack.com failed or timed out.

informational

WHOIS registration data

Registrar: Moniker Online Services LLC | Created: 1998-11-01 | Expires: 2026-10-31 | Updated: 2025-11-25

informational

WHOIS privacy protection enabled

Domain thumbtack.com has WHOIS privacy/redaction enabled.

informational

Dependency Chains

DMARC Authentication Chain (SPF)

DMARC uses SPF to verify that emails come from authorized servers

SPF Record SPF record found and configured → DMARC Policy DMARC policy: reject

DMARC Authentication Chain (DKIM)

DMARC uses DKIM to verify that emails have not been tampered with

DKIM Signature DKIM signature configured → DMARC Policy DMARC policy: reject

Mail Server Identity: aspmx.l.google.com

PTR record proves mail server legitimacy

MX: aspmx.l.google.com Mail server at 172.253.116.27 → PTR Record Reverse DNS: dj-in-f27.1e100.net

Mail Server Identity: alt3.aspmx.l.google.com

PTR record proves mail server legitimacy

MX: alt3.aspmx.l.google.com Mail server at 192.178.213.26 → PTR Record Reverse DNS: yugrqzs-in-f26.1e100.net

Mail Server Identity: alt4.aspmx.l.google.com

PTR record proves mail server legitimacy

MX: alt4.aspmx.l.google.com Mail server at 142.251.127.26 → PTR Record Reverse DNS: lcfrai-in-f26.1e100.net

Mail Server Identity: alt1.aspmx.l.google.com

PTR record proves mail server legitimacy

MX: alt1.aspmx.l.google.com Mail server at 173.194.76.26 → PTR Record Reverse DNS: ws-in-f26.1e100.net

Mail Server Identity: alt2.aspmx.l.google.com

PTR record proves mail server legitimacy

MX: alt2.aspmx.l.google.com Mail server at 142.250.102.26 → PTR Record Reverse DNS: rb-in-f26.1e100.net

Mail Server Reputation: aspmx.l.google.com