In addition to the significant indirect problems with ICQ, straightforward security problems have occurred with the ICQ client itself. These are mostly denial of service attacks where people can crash or hang the machine running the client, but some of them have been buffer overflow problems that could allow an attacker to run arbitrary commands. In addition, one version of the client set up a web server as well as the ICQ client. This is unpleasant for security no matter what web server it is (the vulnerabilities of a web server are quite a bit larger than those of a chat client) and was made worse by the fact that the particular web server that Mirabilis provided allowed any file on the machine to be transferred. Although these problems have been rapidly corrected by Mirabilis, the history of repeated problems is a cause for concern.