[UNIX] GWCC Insecure Temporary File Creation

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  GWCC Insecure Temporary File Creation
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SUMMARY

" <http://gwcc.sourceforge.net/> GWCC allows users to execute network 
utilities (ping, nslookup, traceroute) and workstation commands (netstat, 
df, process grep) from a single tabbed window."

GWCC creates temporary files in an insecure manner that allow local 
attackers to perform symbolic link attacks.

DETAILS

Vulnerable Systems:
 * gwcc version 0.9.6-r2 and prior

GWCC creates a constant temporary file on user home directory, or in the 
/tmp directory if the environment variable is null.

An cause GWCC to create the temporary file name in the /tmp directory, and 
overwrite files using a symbolic link attack.


Possible Patch:
 <http://bugs.gentoo.org/attachment.cgi?id=67477> 
http://bugs.gentoo.org/attachment.cgi?id=67477:
diff -ru gwcc-0.9.6/src/callbacks.c gwcc-0.9.6.new/src/callbacks.c
--- gwcc-0.9.6/src/callbacks.c 2001-07-26 19:50:16.000000000 +0100
+++ gwcc-0.9.6.new/src/callbacks.c 2005-09-02 14:19:39.344296608 +0100
@@ -1697,10 +1697,14 @@
     }
 
     // Create temp file to be Printed (via file saving function).
-  perform_file_save("temp", NULL);
+  if (perform_file_save("temp", NULL) != 0)
+ return;
 
     // Pipe print command and voila!, the doc is printed.
-  strcat(print_command, " /tmp/gwcc_out.txt");
+  snprintf (print_command + strlen(print_command),
+  sizeof(print_command) - strlen(print_command) - 1,
+  " %s%s", getenv("HOME"), "/gwcc_temp.txt");
+
     if (system(print_command) == -1) {
 //    sprintf(entry_text, "The System Call '%s' failed!", print_command);
         
gnome_dialog_run_and_close(GNOME_DIALOG(gnome_error_dialog(entry_text)));
diff -ru gwcc-0.9.6/src/prefs.c gwcc-0.9.6.new/src/prefs.c
--- gwcc-0.9.6/src/prefs.c 2001-07-15 07:00:30.000000000 +0100
+++ gwcc-0.9.6.new/src/prefs.c 2005-09-02 14:04:41.998713872 +0100
@@ -27,6 +27,7 @@
    #include <string.h>       /* for string functs */
    #include <fcntl.h>       /* for open() command */
    #include <sys/stat.h>      /* for mkdir() funct */
+  #include <errno.h>
    #include "prefs.h"
    #include "interface.h"
    #include "support.h"
diff -ru gwcc-0.9.6/src/utils.c gwcc-0.9.6.new/src/utils.c
--- gwcc-0.9.6/src/utils.c 2001-05-15 04:42:21.000000000 +0100
+++ gwcc-0.9.6.new/src/utils.c 2005-09-02 14:20:07.050084688 +0100
@@ -91,16 +91,15 @@
         }
         gtk_widget_destroy(GTK_WIDGET(user_data));
     }
-  else if (strcmp(operation, "temp") == 0) {
-    strcat(file_name, "/tmp/gwcc_out.txt");
-  }
-  else if (strcmp(operation, "home") == 0) {
-    env_homedir = getenv("HOME");
-    if (env_homedir == NULL) {
-      strcpy(env_homedir, "/tmp");
-    }
-    strcpy(file_name, env_homedir);
-    strcat(file_name, "/gwcc_out.txt");
+  else if ((strcmp(operation, "temp") == 0) || strcmp(operation, "home") 
== 0) {
+ env_homedir = getenv("HOME");
+ if (env_homedir == NULL)
+  return 1;
+ strcpy(file_name, env_homedir);
+ if (strcmp(operation, "home") == 0)
+  strcat(file_name, "/gwcc_out.txt");
+ else
+     strcat(file_name, "/gwcc_temp.txt");
     }
 
     // Get the number (int) of current notebook page (0...n-1),


ADDITIONAL INFORMATION

The information has been provided by  <mailto:exploits@xxxxxxxxx> ZATAZ 
Audits.
The original article can be found at:  
<http://www.zataz.net/adviso/gwcc-09052005.txt> 
http://www.zataz.net/adviso/gwcc-09052005.txt



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