We ran Nessus on a Linux system and found that stunnel crashes when the weak certificate suite is enabled. GDB shows the stack trace below and it appears to be in the SSL library. My search on this mailing list led me to this message that appears to report a similar problem
http://mirt.net/pipermail/stunnel-users/2008-January/001830.html
Am I to understand that the problem is really with OpenSSL and that's what needs to be upgraded? If so, do we know what version will have the fixed problem?
I'm going to post in the OpenSSL forum as well, but I wanted to start here since from our perspective, Stunnel is the one crashing.
Thank you
Roger Cruz
2010.02.05 12:49:11 LOG7[13524:3086718672]: Cleaning up the signal pipe
2010.02.05 12:49:11 LOG6[13524:3086718672]: Child process 13575 finished with code 0
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb7fa7b90 (LWP 13574)]
0x007b24a7 in krb5_is_referral_realm () from /usr/lib/libkrb5.so.3
(gdb) bt
#0 0x007b24a7 in krb5_is_referral_realm () from /usr/lib/libkrb5.so.3
#1 0x0089d338 in kssl_keytab_is_available () from /lib/libssl.so.6
#2 0x008803b1 in ssl3_choose_cipher () from /lib/libssl.so.6
#3 0x0087b2a2 in ssl3_get_client_hello () from /lib/libssl.so.6
#4 0x0087bc85 in ssl3_accept () from /lib/libssl.so.6
#5 0x0089109a in SSL_accept () from /lib/libssl.so.6
#6 0x00884d0d in ssl23_get_client_hello () from /lib/libssl.so.6
#7 0x0088554b in ssl23_accept () from /lib/libssl.so.6
#8 0x0089109a in SSL_accept () from /lib/libssl.so.6
#9 0x003628e2 in ?? () from /usr/sbin/stunnel
#10 0x00363acd in ?? () from /usr/sbin/stunnel
#11 0x003645ba in ?? () from /usr/sbin/stunnel
#12 0x003646a8 in client () from /usr/sbin/stunnel
#13 0x0025f45b in start_thread () from /lib/libpthread.so.0
#14 0x00448e5e in clone () from /lib/libc.so.6
(gdb) quit
[root@p20xen1 current_hq]# stunnel -version
stunnel 4.15 on i686-redhat-linux-gnu with OpenSSL 0.9.8b 04 May 2006
Threading:PTHREAD SSL:ENGINE Sockets:POLL,IPv6 Auth:LIBWRAP
Global options
debug = 5
pid = /var/run/stunnel.pid
RNDbytes = 64
RNDfile = /dev/urandom
RNDoverwrite = yes
Service-level options
cert = /etc/stunnel/stunnel.pem
ciphers = ALL:!ADH:+RC4:@STRENGTH
key = /etc/stunnel/stunnel.pem
session = 300 seconds
TIMEOUTbusy = 300 seconds
TIMEOUTclose = 60 seconds
TIMEOUTconnect = 10 seconds
TIMEOUTidle = 43200 seconds
verify = none