Phenoelit Advisory <wir-haben-auch-mal-was-gefunden #0815 +-++->
[ Authors ]
joernchen <joernchen () phenoelit de>
Phenoelit Group (http://www.phenoelit.de)
[ Affected Products ]
sup <= 0.14.1 (on non Darwin systems)
sup <= 0.13.2 (on non Darwin systems)
http://supmua.org
[ Vendor communication ]
2013-10-28 Send vulnerability details to sup maintainer
2013-10-28 Maintainer proposes fix
2013-10-29 Sup 0.13.2.1 and 0.14.1.1 are released [1]
2013-10-29 Release of this advisory
[ Description ]
Observe in sup/lib/sup/message_chunks.rb:
def view_default! path
## please see note in write_to_disk on important usage
## of quotes to avoid remote command injection.
case RbConfig::CONFIG['arch']
when /darwin/
cmd = "open #{path}"
else
cmd = "/usr/bin/run-mailcap --action=view #{@content_type}:#{path}"
end
debug "running: #{cmd.inspect}"
BufferManager.shell_out(cmd)
$? == 0
end
Here @content_type is attacker controlled and not further
sanitized. By this a forged content type of an email
attachment can trigger a command injection.
[ Example ]
For convenience the email delivering this file serves as an
example. When viewing this attachment in a vulnerable version
of sup the content type being "text/'`id>/tmp/whatsup`'pwn"
will generate a file "whatsup" in the /tmp directory.
[ Solution ]
Upgrade to version 0.14.1.1 or 0.13.2.1
[ References ]
[0] https://github.com/sup-heliotrope/sup/blob/916a354db8eb851bff6ff2e3f2e08727d132a8dc/lib/sup/message_chunks.rb#L175
[1] http://rubyforge.org/pipermail/sup-talk/2013-October/004996.html
[ end of file ]
