Tutorial - Possible Buffer Overflow in Cmail

## Possible Buffer Overflow in Cmail

CVE 2000-0556
CVE 2000-0557

### Impact

If the system has this buffer overflow condition, an attacker could send a specially constructed request which crashes the server or executes arbitrary code.

Note: While the red stoplight on this page indicates the highest possible severity level for this vulnerability, the severity level in this particular instance is indicated next to the link to this tutorial on the previous page. If there is a red dot, your server is vulnerable. If there is a brown dot, the vulnerability could not be confirmed, and you should determine whether or not your server is vulnerable based on the information below.

### Background

The Cmail application is a mail server which runs on Microsoft operating systems and provides e-mail services. Cmail is compatible with many popular e-mail clients, and also has a web-based interface. The web server runs on port 8002 by default.

### The Problem

CVE 2000-0557
Due to a buffer overflow condition in `NTDLL.DLL`, an attacker could execute arbitrary code by sending a large, specially crafted `GET` command to the web server. Cmail version 2.4.7 and possibly prior versions are vulnerable.

CVE 2000-0556
Due to a second, unrelated vulnerability, a denial-of-service attack is possible whereby an attacker could consume up to 95% of the server's CPU time.

### Resolutions

Upgrade to Cmail version 2.4.8 or higher.

### Where can I read more about this?

This vulnerability was posted to NT Bugtraq.