A pair of German researchers at next week's Black Hat Europe will release tools that hack backbone technologies used by service providers in some enterprise network service offerings.

More specifically, the tools -- built by Enno Rey and Daniel Mende, both with German security firm ERNW -- automate attacks on Multiprotocol Layer Switching (MPLS) and Ethernet backbone technologies. They exploit similar, inherent security weaknesses in the two networking technologies -- namely, in how they forward traffic.

The lack of security in MPLS and Ethernet is well-known, but until now the exploitation of these network technologies has been only theoretically possible, Rey says. "Our release of the tools closes that gap of these attacks being only theoretical to being practically exploitable now," he says. "These technologies do not provide any security themselves, but just rely on the assumption that the underlying network is secure."

Network infrastructure security has been in the limelight lately, with researchers uncovering big vulnerabilities in the Domain Name System (DNS), the Border Gateway Protocol (BGP), TCP, and in Cisco routers.

MPLS VPNs originally were proprietary networks when they first hit the network scene. But the evolution of service provider networks to Internet-based services has put MPLS, as well as Ethernet, in the hot seat as possible hacking targets, Rey notes. MPLS networks used to have their "own set of switches and management infrastructures, and their own set of surrounding technologies," he says, "and the average attacker could not get his hands on that equipment."

To execute an MPLS or Ethernet carrier network hack, an attacker first must get into the network, either by hacking a router or a management tool. Then Rey and Mende's MPLS hacking tool could be used: It modifies the labels that are added to packets in an MPLS network and determines how those packets are forwarded. This lets an attacker silently redirect traffic to other sites, such as a malicious DNS server or a phony authentication server, Rey says. "The victim doesn't notice anything...and the attacker has both directions of traffic [in his control]," he says. "The whole VPN model of trust is violated."

The attack doesn't target a specific vulnerabilty -- just the way MPLS operates. The story is much the same for Ethernet. VLAN-tagging, for instance, helps carriers separate different customers' traffic across their backbones. "But there's no encryption and no additional security [with Ethernet]," Rey says. "It's just traffic separated by adding some more bits to the traffic, which brings us back to being able to modify those bits [with our hacking tool]."

Rey says enterprises that use these VPN services should be aware they are vulnerable. Perform risk analysis and encrypt your traffic, he says. "Just because it's called MPLS VPN [doesn't mean] you should [automatically] trust it," he says.

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