[nsp-sec] spam sender email addresses begnning with '-'

[Torbjorn.Wictorin at cert.sunet.se]

hi,

for about a week or so a large part of the spam coming to our cert@
address has a from-address that starts with a - (minus) sign.
(Like -na111 at jfkaz.com)
A bit odd. Anyone who has seen the same and got an idéa why?

Torbjörn Wictorin
Sunet CERT