ct-exposer will query the CT logs for a given domain, and then try to do DNS lookups for the domains to see which ones exist in DNS. In my experience, so far, I’ve found numerous sub-domains that were not located with ‘site:domain.com’ google searches.

Keep in mind that the domains that do not resolve, they can either be old domains, or internal only domains (Ex: you need access to the internal DNS server to resolve them).

Certificate Transparency (CT) is an experimental IETF standard. The goal of it was to allow the public to audit which certificates were created by Certificate Authorities (CA). TLS has a weakness that comes from the large list of CAs that your browser implicitly trusts.

If any of those CAs were to maliciously create a new certificate for a domain, your browser would trust it. CT adds benefits to TLS certificate trust: Companies can monitor who is creating certificates for the domains they own.

It also allows browsers to verify that the certificate for a given domain is in the public log record. These logs end up being a gold mine of information for penetration testers and red teams.

ct-exposer Usage

usage: ct-exposer.py [-h] -d DOMAIN [-u] [-m]

optional arguments:
  -h, --help            show this help message and exit
  -d DOMAIN, --domain DOMAIN
                        domain to query for CT logs, ex: domain.com
  -u, --urls            ouput results with https:// urls for domains that
                        resolve, one per line.
  -m, --masscan         output resolved IP address, one per line. Useful for
                        masscan IP list import "-iL" format.

Also ReadInfog – Information Gathering Tool

Example output

python3 ct-exposer.py -d teslamotors.com
[+]: Downloading domain list...
[+]: Download of domain list complete.
[+]: Parsed 76 domain(s) from list.

[+]: Domains found:
205.234.27.243	adfs.teslamotors.com
104.92.115.166	akamaisecure.qualtrics.com
211.147.80.202	cn.auth.teslamotors.com
211.147.88.104	cnvpn.teslamotors.com
209.10.208.24	energystorage.teslamotors.com
209.11.133.110	epc.teslamotors.com
149.14.82.93	euvpn.teslamotors.com
209.11.133.50	extconfl.teslamotors.com
209.11.133.35	extissues.teslamotors.com
209.10.208.31	fleetview.teslamotors.com
64.125.183.134	leaseapp.teslamotors.com
64.125.183.134	leaseappde.teslamotors.com
209.11.133.11	lync.teslamotors.com
211.147.80.201	mycn-origin.teslamotors.com
205.234.27.211	origin-www45.teslamotors.com
205.234.31.120	owner-api.teslamotors.com
12.201.132.70	plcvpn.teslamotors.com
205.234.27.246	quickbase.teslamotors.com
104.86.205.249	resources.teslamotors.com
209.10.208.55	sdlcvpn.teslamotors.com
209.11.133.37	service.teslamotors.com
205.234.27.226	sftp.teslamotors.com
23.227.38.64	shop.eu.teslamotors.com
209.133.79.61	shop.teslamotors.com
23.227.38.64	shop.uk.teslamotors.com
205.234.27.197	smswsproxy.teslamotors.com
209.11.133.36	supercharger.teslamotors.com
209.133.79.59	suppliers.teslamotors.com
209.133.79.61	tesla.com
209.11.133.106	teslamotors.com
205.234.27.200	teslaplm-external.teslamotors.com
209.11.133.107	toolbox.teslamotors.com
209.10.208.20	trt.teslamotors.com
205.234.27.250	upload.teslamotors.com
209.10.208.27	us.auth.teslamotors.com
205.234.27.218	vpn.teslamotors.com
211.147.80.205	wechat.teslamotors.com
205.234.27.212	wsproxy.teslamotors.com
209.133.79.54	www-origin.teslamotors.com
104.86.216.34	www.teslamotors.com
209.11.133.61	xmail.teslamotors.com
211.147.80.203	xmailcn.teslamotors.com

[+]: Domains with no DNS record:
none	cdn02.c3edge.net
none	creditauction.teslamotors.com
none	evprd.teslamotors.com
none	imail.teslamotors.com
none	jupytersvn.teslamotors.com
none	leadgen.teslamotors.com
none	lockit.teslamotors.com
none	lockpay.teslamotors.com
none	neovi-vpn.teslamotors.com
none	origin-wte.teslamotors.com
none	referral.teslamotors.com
none	resources.tesla.com
none	securemail.teslamotors.com
none	shop.ca.teslamotors.com
none	shop.no.teslamotors.com
none	sip.teslamotors.com
none	sjc04p2staap04.teslamotors.com
none	sling.teslamotors.com
none	tesla3dx.teslamotors.com
none	testimail.teslamotors.com
none	toolbox-energy.teslamotors.com
none	vpn-node0.teslamotors.com
none	wd.s3.teslamotors.com
none	www-uat2.teslamotors.com
none	www45.teslamotors.com

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