| Plugin ID | 7 |
| Plugin name | SMTP HELP detection |
| Plugin filename | SMTP HELP detection.plugin |
| Plugin filesize | 2645 bytes |
| Plugin family | SMTP |
| Plugin created name | Marc Ruef |
| Plugin created email | marc dot ruef at computec dot ch |
| Plugin created web | http://www.computec.ch |
| Plugin created company | computec.ch |
| Plugin created date | 2003/11/13 |
| Plugin updated name | Marc Ruef |
| Plugin updated email | marc dot ruef at computec dot ch |
| Plugin updated web | http://www.computec.ch |
| Plugin updated company | computec.ch |
| Plugin updated date | 2004/11/13 |
| Plugin version | 2.0 |
| Plugin changelog | Corrected the plugin structure and added the accuracy values in 1.3. Improved the pattern matching and added the changelog in 2.0 |
| Plugin protocol | tcp |
| Plugin port | 25 |
| Plugin procedure detection | open|send HELP\n|sleep|close|pattern_exists 220 *HELP* |
| Plugin detection accuracy | 70 |
| Plugin comment | This plugin was written with the ATK Attack Editor. |
| Bug affected | Most mail transfer agents |
| Bug not affected | Hardened mail transfer agents |
| Bug vulnerability class | Configuration |
| Bug description | The mail server allows the HELP commando. A malicous user could use this to verify the availablity of certain SMTP commands. He could also enumerate the mail server. |
| Bug solution | Do not allow the HELP command to prevent further enumeration. Check the manual of your mail server howto set the configuration correctly. Additionally prevent unwanted SMTP connections with firewalling. |
| Bug fixing time | 10 minutes |
| Bug exploit availability | Yes |
| Bug remote | Yes |
| Bug local | Yes |
| Bug severity | Low |
| Bug popularity | 9 |
| Bug simplicity | 9 |
| Bug impact | 2 |
| Bug risk | 6 |
| Bug check tools | Nessus is able to do the check automated. Mostly attackers prefer to test the HELP support with a simple telnet or NetCat connection. |
| Source Literature | Hacking Intern - Angriffe, Strategien, Abwehr, Marc Ruef, Marko Rogge, Uwe Velten and Wolfram Gieseke, November 1, 2002, Data Becker, D�sseldorf, ISBN 381582284X |
| Source Misc. | http://www.computec.ch |