[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@zataz.net> 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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