Security Threats

To provide your employees the flexibility to work from anywhere while allowing them the ability to communicate with coworkers and partners and customers as if they were at the office, you need to enable users for remote access. This means deploying an Edge Server or Edge pool and publishing Skype for Business (formerlyn known as Lync) through a reverse proxy. This creates multiple network pathways into your corporate network that Skype for Business clients utilize. Skype for Business Server makes use of many communication protocols.

  • SIP and UCWA over HTTPS for signaling and messaging
  • PSOM for desktop and application sharing
  • SRTP for audio and video traffic
  • WOPI over HTTPS for PowerPoint sharing using Office Web Apps Server
  • EWS over HTTPS for calendar information from Exchange Server

These protocols are susceptible to attack even if they're encrypted to prevent eaves dropping and users are authenticated. These protocols are most susceptible to attack in the initial communication before the user is authenticated. In some cases, the user isn't authenticated as in the case of allowing external anonymous users to join an internal Skype for Business online meeting.

Users must first authenticate via SIP and HTTPS. After authentication, they can access Skype for Business and Exchange resources as the other protocols piggy-back on the authentication performed over SIP and HTTPS.


This is where active edge protection is needed. The Security Edge Filter protects the SIP protocol over TLS traffic, and the Security Web Filter protects the UCWA, WOPI and EWS protocols over HTTPS traffic. Combined, these server products protect at the perimeter edge user accounts and internal servers against denial of service (DoS) attacks, invalid requests in an attempt to tie up internal resources, scripting attacks on meeting URLs and many other types of attacks.

The Security Edge Filter and Security Web Filter are part of the Security Filters suite of security products designed specifically to scan Skype for Business, Exchange and Office Web Apps network protocols.

Key Benefits

  • Protect corporate user accounts from being locked out
  • Shield internal servers from external attacks
  • Filters out invalid external requests
  • Enforce stronger authentication (TLS-DSK)
  • Deep scanning of Skype for Business and Exchange traffic

Centralized Management

Each of the Security Filter products are integrated with the Security Filter Manager. The Security Filter Manager provides centralized logging and administration, making it simpler for administrators to manage all your instances of Security Filter components.


The Security Edge Filter and Security Web Filter are offered in two editions:

For customers with a single Edge Server or reverse proxy.
For customers with multiple Edge Servers and reverse proxy. Requires SQL Server.
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