SEC Consult SA-20240524-0 :: Exposed Serial Shell on multiple PLCs in Siemens CP-XXXX Series
2024-5-28 10:50:34 Author: seclists.org(查看原文) 阅读量:8 收藏

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From: SEC Consult Vulnerability Lab via Fulldisclosure <fulldisclosure () seclists org>
Date: Fri, 24 May 2024 06:37:00 +0000

SEC Consult Vulnerability Lab Security Advisory < 20240524-0 >
=======================================================================
              title: Exposed Serial Shell on multiple PLCs
            product: Siemens CP-XXXX Series (CP-2014, CP-2016, CP-2017, CP-2019, CP-5014)
 vulnerable version: All hardware revisions
      fixed version: Hardware is EOL, no fix
         CVE number: -
             impact: Low
           homepage: https://www.siemens.com
              found: ~2023-06-01
                 by: Steffen Robertz (Office Vienna)
                     Gerhard Hechenberger (Office Vienna)
                     Constantin Schieber-Knöbl (Office Vienna)
                     SEC Consult Vulnerability Lab

                     An integrated part of SEC Consult, an Eviden business
                     Europe | Asia

                     https://www.sec-consult.com

=======================================================================

Vendor description:
-------------------
"We are a technology company focused on industry, infrastructure,
transport, and healthcare. From more resource-efficient factories,
resilient supply chains, and smarter buildings and grids, to cleaner
and more comfortable transportation as well as advanced healthcare,
we create technology with purpose adding real value for customers."

Source: https://new.siemens.com/global/en/company/about.html


Business recommendation:
------------------------
The hardware is no longer produced nor offered to the market. Hence
HW adaptions resulting in modified products are not possible anymore.
The described HW behavior on this generation of devices cannot be
corrected by means of FW patches.

The risk of successful exploitation is considered low as physical access to
those devices is needed.

SEC Consult highly recommends to perform a thorough security review of the product
conducted by security professionals to identify and resolve potential further
security issues.


Vulnerability overview/description:
-----------------------------------
1) Exposed Serial Shell on multiple Siemens PLCs
A serial interface can be accessed with physical access to the PCB. After
connecting to the interface, access to a shell with various debug functions
as well as a login prompt is possible.


Proof of concept:
-----------------
1) Exposed Serial Shell on multiple Siemens PLCs

* CP-2016 (Figure 1)
The serial interface on the CP-2016 can be accessed by connecting to the
following through hole pins of an unpopulated header:

 +-+
 |o|
 |o|RX
 |o|TX
 |o|
 |o|
 |o|GND
 +-+

* CP-2019 (Figure 2)
The serial interface on the CP-2019 can be accessed by connecting to the
following through hole pins of an unpopulated header:

 +-+
 |o|
 |o|RX
 |o|TX
 |o|
 |o|
 |o|GND
 +-+

 * CP-2014 (Figure 3)
The serial interface on the CP-2014 can be accessed by connecting to the
following through hole pins of an unpopulated header:

 +-+
 |o|GND
 |o|
 |o|
 |o|RX
 |o|TX
 |o|
 +-+

 * CP-2017 (Figure 4)
The serial interface on the CP-2017 can be accessed on the compute module
by connecting to pins 9 and 10 on the populated SMD connector:

  1              TX RX
  '-'-'-'-'-'-'-'-'-'
 /-------------------\
 |                   |
 |-------------------|
 +'-'-'-'-'-'-'-'-'-'+
  11                20


* CP-5014 (Figure 5)
The serial interface on the CP-5014 can be accessed on the compute module
by connecting to pins 1 and 2 on the populated SMD connector:

 RX TX              10
  '-'-'-'-'-'-'-'-'-'
 /-------------------\
 |                   |
 |-------------------|
 +'-'-'-'-'-'-'-'-'-'+
  11                20


All serial connections allow access to the SH1703 shell in version 1.00.
The shell requires no authentication and allows the usage of multiple
commands.

The following output can be seen on all devices:

---------------------------------------------------
   XXXXX  XXX XXX      X     XXXXX    XXX     XXX
  X     X  X   X     XXX     X   X   X   X   X   X
  X        X   X       X        X    X   X       X
   XXXXX   XXXXX       X        X    X   X     XX
        X  X   X       X       X     X   X       X
  X     X  X   X       X      X      X   X   X   X
   XXXXX  XXX XXX    XXXXX    X       XXX     XXX
---------------------------------------------------

1703 Shell [V1.00]
(c) by 1703 Development Team

type 'help' or '?' or press 'F1' for help

SH1703>

Initialize system ..
. Init Done.

system startup after Power-Up ...
Install device 'USB Server'.

 RTC time not valid

 RTC time not valid

 RTC time not valid
Reg: 100 Komp: 2 BSE: 20
Hello from <R#100 / K#2 / BSE#2> FW-ID: 2019 FW-Version: 0.06A01
Startup ZBGs ... done.

system ready
SH1703>help
Available commands:
 hist                             Display command history
!<n>                             Execute <n> command from stack
 ?        [<cmd>]                 Display this message
 help     [<cmd>]                 Display this message
 echo     <text>                  Displays text
 call     <file>                  Run script file
 cls                              Clear screen
 loop     <cmd>                   Loop-execution of cmd
 ldfile   <file>                  Load ascii file
 db       <a> [-b|w|d<x> [-n<x>]] Display memory byte/word/dword
 wb       <a> <val> [-b|w|d<x>]   Write memory byte/word/dword
 mb       <a> [-b|w|d<x> [-n<x>]] Monitoring memory byte/word/dword
 login                            Login
 logoff                           Logoff
 pci      ...                     PCI Commands
 bemrk                            Run Benchmark
 drv                              List installed drives
 dir                              List files in directory
 del      [<drv:>]<file>          Delete file
 ren      <src> <dest>            Rename or move file
 cd       <dir>|<..>              Change current directory or drive
 md       <dir>                   Make directory
 rd       <dir>                   Remove directory
 type     [<drv:>]<file>          Displays the contents of a file
 copy     <src> <dest>            Copy a file
 findstr  <file> <str>            Find a string in a textfile
 mkdisk   <drvname> <size>        Make a Ramdisk
 uidisk   <drvname>               Close and uninstall a disk
 format   <drvname>               Format drive
 mem_wr   <addr> <size> <des>     Write mem to file
 idr                              Read from diagnostic ring
 icr                              Clear diagnostic ring
 idd                              Debug-Trace ON
 bp                               Read all breakpoint settings
 bpf      [<file>]                Set File for Debugprint (no arg = stdout)
 is       ...                     Debugger settings
 ig       [f|s]                   Display BPs / Clear all BPs
 idb                              Read DB-Breaks
 idt                              Read DB-Trace Settings
 icz                              Clear breakpoint counters
 dev      ...                     ZIO-Device commands
 bsp      ...                     bsp commands
 ftrc     ...                     FTRC Commands
 banner                           Display the banner
 pl                               Display process list
 pi       [<appl_nr>]             Display process info
 ad       -c|d|k|s                APP-Debug Create|Detach|Kill|Start
 tl                               Display task list (all processes)
 tm       [-r]                    Display task monitor (-r = runtime)
 tc       <taskname>              Display task context
 td       <taskID>                Display task descriptor
 tq                               Display task queues
 sysztsk                          Display ZOS-tasks of system process
 appztsk  [<appl_nr>]             Display ZOS-tasks of appl-process(es)
 stack                            Display stack usage of all tasks
 stsk     -c|d|e|s|r              ZOS-Task Create|Del|Exch|Suspend|Resume
 tsktrc   -s|r|c                  ZOS-Task-Trace Start|Read|Clear
 set      [<name>=<val>]          Display, set or remove environment variables
 time                             Display the current time
 timeset                          Set the current time
 mem                              Display memory usage
 status                           Display system status informations
 ver                              Display version informations
 r                                Reset system element (R,R Cxx,R Pxx,R Zxx
 klog     [dis|ena|all]           Display, disable or enable kernel logging
 psp_info                         Display prozessor configuration infos
 int_info                         Interrupt-Info-List
 int_gen                          Generate Interrupt (for Admin only)
 tlbs                             Display TLBs
 ga       [<appl_nr>]             Start Subshell of application
 tsd                              Debug Timeserver
 mci                              MCI Commands
 usb      <cmd>                   USB commands
 mmc      <cmd>                   MMC Commands
 zhs                              ZHS commands
 zpv                              Parameter infos
 zdt                              data transporter
 fsn                              ZIO/FSN statistics
 net      <enet|emac|mal> <dev>   Network statistics
 prd      <pg> <reg> <len>        Read PHY register (len: 8|16|32)
 pwr      <pg> <reg> <len> <data> Write PHY register (len: 8|16|32)
 rmib                             Reset all statistic counters
 scfg                             Display broadcom switch registers
 ipaddr   <dev>                   Display ip addresses on interface
 route                            Display routing table
 socket                           Display socket statistic
 tcp                              Display tcp statistic
 udp                              Display udp statistic
 arp                              Display arp cache
 ping     host-ipaddr             send ICMP ECHO_REQUEST to a host
 arl                              Switch Address Resolution table
 ebuf                             Statistic for Buffer handling FSN
 tls_ciph                         print cipher suites for all connections
 tls_obj  idx                     print connection objects
 tls_log                          log level for tls lib
 tls_deb  idx                     print connection debug cnts
 tlscache                         print cert/key cache
 opensslm                         print mem pool statistic for openssl
 tlsdeb_s                         START mem pool debug function
 tlsdeb_e                         END mem pool debug function
 tlsdeb_r                         print mem pool debug for openssl
 tlsdeb_c                         CLEAR mem pool debug function
 sap                              special application function
Available Function-Keys:
 F1     Help
 F2     Display system status informations
 F3     Display Last command
 F5     Display the current time
 F7     History
 F8     Display memory usage
 F9     Display ZOS-Task Infos
 F10    Display Tasklist
 F11    Execute Last command
SH1703>

----------------------------------------


Vulnerable / tested versions:
-----------------------------
The following versions have been tested which were the latest version available
at the time of the test:
* CP-2016: CPCX26 V0.06A01
* CP-2019: PCCX26 V0.06A01
* CP-2014: CPCX25 V0.05A04
* CP-2017: PCCX25 V0.11A10
* CP-5056: CPCX55 V0.10A04


Vendor contact timeline:
------------------------
2024-03-05: Contacting vendor through productcert () siemens com
2024-03-06: Siemens tracks this issue as case #04393
2024-04-03: Requested status update.
2024-04-03: Product is EOL, no fix planned.
2024-04-29: Informed Siemens about planned publication of advisory.
2024-04-30: Siemens, requests draft of advisory. Advisory is sent for review.
2024-05-07: Siemens requested small changes in the Solution and Business
            Recommendation.
2024-05-24: Public release of security advisory.


Solution:
---------
The hardware is no longer produced nor offered to the market. Hence HW
adaptions resulting in modified products are not possible anymore. The
described HW behavior on this generation of devices cannot be corrected
by means of FW patches.

The risk of successful exploitation is considered low as physical access to
those devices is needed.


Workaround:
-----------
Make sure to strictly limit physical access to the PLC during and also
after its life cycle.


Advisory URL:
-------------
https://sec-consult.com/vulnerability-lab/


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

SEC Consult Vulnerability Lab
An integrated part of SEC Consult, an Eviden business
Europe | Asia

About SEC Consult Vulnerability Lab
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult, an
Eviden business. It ensures the continued knowledge gain of SEC Consult in the
field of network and application security to stay ahead of the attacker. The
SEC Consult Vulnerability Lab supports high-quality penetration testing and
the evaluation of new offensive and defensive technologies for our customers.
Hence our customers obtain the most current information about vulnerabilities
and valid recommendation about the risk profile of new technologies.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Send us your application https://sec-consult.com/career/

Interested in improving your cyber security with the experts of SEC Consult?
Contact our local offices https://sec-consult.com/contact/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Mail: security-research at sec-consult dot com
Web: https://www.sec-consult.com
Blog: https://blog.sec-consult.com
Twitter: https://twitter.com/sec_consult

EOF Steffen Robertz, Gerhard Hechenberger, Constantin Schieber-Knöbl / @2024

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