Use telnet to manually query an SMTP server to identify the presence of user names
- [Voiceover] Numeration is usually carried out…by running tools to list object instances.…But it can also done indirectly…by checking whether objects exist.…An example of this approach is used…to enumerate an ESMTP service.…We can connect to ESMTP by using Telnet.…I'll connect to the metasplotable ESMTP…server using port 25.…I can now ask the server to verify an email address.…
The server tells me that the email address doesn't exist.…With the fail e-code 511.…I can ask the server to verify msfadmin.…And the server responds with code 2.0.0,…the email address exists.…I can try more potentially email addresses.…We can also use the receipt command…to detect the existence of email addresses.…
The valid email address, results in the 2.1.5 success code.…But in this case, the incorrect email…address results in a 5.1.1 failure code.…By using a set of common email addresses,…this technique can be used to detect whether…or not those addresses are active in the ESMTP system.…
An overview of the CEH exam, blueprint, and eligibility criteria can be found at https://www.eccouncil.org/programs/certified-ethical-hacker-ceh/.
- What is enumeration?
- Understanding NetBIOS, SMB, SAMBA, and RPC
- Profiling hosts
- Investigating interfaces
- Enumerating SMB
- Enumerating SNMP and RPC
- Enumerating the Internet
- Working with other enumeration tools
Skill Level Intermediate
1. Basics of Enumeration
2. Local Host Enumeration
3. Remote Hosts
4. Enumerating the Internet
5. Other Enumeration Tools
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