Product: Hypermail
Vendor: Hypermail Development (http://www.hypermail.org)
Severity: Remote; Attacker may be able to execute arbitrary commands on servers that run Hypermail and SSI
Vendor Status: Vendor contacted; patch released
In Short: Hypermail can be used to create arbitrary files, with arbitrary extensions, on the server, which may then possibly be used to execute SSI commands.
Hypermail converts e-mails into HTML. It is generally used to automatically create web archives of mailing lists. When e-mails are
archived, attachments which are included are archived as well. The attachments are not modified before archival, and they are stored under
the filename contained in the e-mail.
An attacker can therefore create an arbitrary file on the web server with an arbitrary extension. If the server supports SSI, an attacker can include
SSI commands in a file, give it the SSI extension (normally .shtml), and mail it. This will create the desired file on the server. The
attacker can than cause the server to execute those SSI commands by requesting the attachment.
It should be noted that creation of arbitrary files on a web server carries with it additional insecurites besides SSI, and therefore
even servers that do not support SSI may be vulnerable.
Solution: Hypermail has been patched to convert .shtml extensions to .html. As of this writing, no further correction has been taken.
Servers should never allow SSI, CGI, or any other type of server processed content in the hypermail directory.
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