What causes exim to sigterm?

[bls24]

I had exim call a sigterm in the middle of a cron last night. According to the exim_paniclog nothing happened (it was empty).

exim_mainlog has this:

2008-07-28 00:04:25 H=x-x-x-x.fibertel.com.ar (efl-e65d5fddd1e) [190.x.x.x]:3835 I=[x.x.x.x]:25 Warning: Sende$
2008-07-28 00:04:26 H=x-x-x-x.fibertel.com.ar (efl-e65d5fddd1e) [190.x.x.x]:3835 I=[xx.x.x]:25 Warning: "Incr$
2008-07-28 00:04:26 H=x-x-x-x.fibertel.com.ar (efl-e65d5fddd1e) [190.xx.x]:3835 I=[x.x.x.x]:25 F=<dispensersu$
2008-07-28 00:04:26 SMTP connection from x-x-x-x.fibertel.com.ar (efl-e65d5fddd1e) [190.x.x.x]:3835 I=[x.x.x.x$
2008-07-28 00:05:01 cwd=/usr/.tstools 2 args: /usr/sbin/exim -bV
2008-07-28 00:05:02 cwd=/usr/.tstools 4 args: /usr/sbin/exim -bV -C /etc/exim.conf.buildtest.work.8WPJPXpoa6b5B3Qv
2008-07-28 00:05:02 SIGTERM received while reading local message

I have no idea whose IP that is.
Is this person DDoS'ing me?