GEN:SID 1:2335
Message FTP RMD / attempt
Summary This event is generated when an attempt is made to exploit a known
vulnerability in AppleShare IP FTP Server.
Impact Denial of Service (DoS)
Detailed Information FTP is used to transfer files between hosts. This event is indicative of spurious
activity in FTP traffic between hosts.

It is possible for a user to supply data to an FTP command, in this case
RMD, and cause the service to become unavailble to other users.
Affected Systems Apple AppleShare IP 5.0, 5.0.1, 5.0.2, 5.0.3
    Apple AppleShare IP 6.1, 6.2, 6.3, 6.3.1
Attack Scenarios An attacker needs to login to the service and use the RMD command in a
specific manner to cause the DoS.
Ease of Attack Simple. No exploit software required.
Corrective Action Apply the appropriate vendor supplied patches.

Upgrade to the latest non-affected version of the software.

Disallow access to FTP resources from hosts external to the protected network.

Use secure shell (ssh) to transfer files as a replacement for FTP.
Additional References  
Rule References bugtraq: 9159