-------- Original Message -------- Subject: clamav 0.65 remote DOS exploit Date: Mon, 09 Feb 2004 15:24:17 +0100 From: Oliver Eikemeier <[EMAIL PROTECTED]> Organization: Fillmore Labs GmbH - http://www.fillmore-labs.com/ To: [EMAIL PROTECTED] CC: [EMAIL PROTECTED]
Description:
It is trivial to crash clamd using a malformed uuencoded message, resulting in a
denial of service for all programs (e.g. SMTP daemons) relying on clamd running.
The message must only contain one uuencoded line with an illegal line lenght, i.e.
starting with a small letter.
libclamav calculates the line lenght of an uuencoded line by taking the ASCII value
of the first character minus 64 and does an `assert' if the length is not in the
allowed range, effectively terminating the calling program.
How-To-Repeat:
Save the following file to ~/clamtest.mbox, removing the leading 'X':
XFrom - X Xbegin 644 byebye Xbyebye Xend
Then do:
# clamscan --mbox -v ~/clamtest.mbox assertion "(len >= 0) && (len <= 63)" failed: file "message.c", line 887 Abort (core dumped)
or
# clamdscan -v ~/clamtest.mbox; ps ax | grep clam
Fix:
Apply the following patch to libclamav/message.c:
--- libclamav/message.c.orig Wed Nov 5 11:59:53 2003
+++ libclamav/message.c Mon Feb 9 15:17:13 2004
@@ -878,13 +878,16 @@
if(strcasecmp(line, "end") == 0)
break;- assert(strlen(line) <= 62);
+ if(strlen(line) > 62)
+ break;
+
if((line[0] & 0x3F) == ' ')
break;len = *line++ - ' ';
- assert((len >= 0) && (len <= 63)); + if(len < 0 || len > 63) + break;
ptr = decode(line, ptr, uudecode, (len & 3) == 0);
break;References:
FreeBSD PR 62586: <http://www.freebsd.org/cgi/query-pr.cgi?pr=62586>
------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ Qmail-scanner-general mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/qmail-scanner-general
