eggdrop/windrop remote crash vulnerability

Affected software

eggdrop (1.6.19 only, not 1.6.19+ctcpfix)
windrop (1.6.19 only, not 1.6.19+ctcpfix)
all eggdrop/windrop versions and packages which apply Nico Goldes
patch for CVE-2007-2807/SA25276 See: [1]

Vulnerability details

The SA25276 patch ([1]) uses strncpy to fix a buffer overflow vulnerability
in src/mod/server.mod/servmsg.c (gotmsg). The last argument is not checked
for being non-negative, but that can happen if ctcpbuf is "". That causes
a remote crash vulnerability to be exploited by anyone connected to the same
IRC network as eggdrop. The SA25276 patch has been applied to the eggdrop1.6.18
debian package and was later adopted by Eggheads into eggdrop1.6.19.

One possible exploit anyone can send to the IRC server to crash eggdrop:

PRIVMSG eggdrop :\1\1

Resolution

Upgrade to eggdrop/windrop 1.6.19+ctcpfix ([2],[3]), the current cvs versions,
or apply the ctcpfix patch at [2] before compiling.

Disclosure timeline

2009-05-06: Vulnerability discovered and reported to Eggheads.
2009-05-06: Patch committed to cvs.
2009-05-14: New eggdrop and windrop version released with the fix applied.
2009-05-14: Public disclosure.

References

[1] http://bugzilla.eggheads.org/show_bug.cgi?id=462
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=427157
http://www.securityfocus.com/bid/24070
http://secunia.com/advisories/25276
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-2807

[2] http://www.eggheads.org/downloads/
[3] http://windrop.sourceforge.net/downloads.html

Thomas Sader (thommey)

Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/