Weak security in high-speed ADSL modems from Alcatel SA could allow hackers to shut down the device, monitor data flows, and use it for cyber attacks, computer security experts said.
Affected systems are the Alcatel Speed Touch Home ADSL modem and the Alcatel 1000 ADSL Network Termination Device, researchers at the San Diego Supercomputer Center (SDSC) , a unit of the University of California at San Diego, said in a security advisory (
last month. The affected modems are sold worldwide and are widely used in the U.S. as well as other countries.
The devices allow third-party logon for servicing reasons, such as updating the firmware. Due to “weak authentication and access control policies” the function could be abused, SDSC said.
After gaining access a hacker could install malicious code on the modem, such as a network “sniffer” that monitors LAN traffic, SDSC said. The hacker could also use the modem in a DDoS (Distributed Denial of Service) attack.
Alcatel is not impressed with the security alerts, saying that the SDSC was not able to access the modem without exploiting a security flaw unrelated to the Alcatel modems.
To access the modem in three of the four cases described, the device must initially be fooled into thinking the traffic originated from the local network. To do this the attacker must use a system on the LAN side of the ADSL modem to relay traffic to the modem. This is done via the UDP (User Datagram Protocol) echo service, which should be disabled.
“This is a general network security issue,” said Karsten Verhaegen, business development director for ADSL modems at Alcatel. “We advise all users to install firewall software to protect themselves from issues like these.”
In the fourth case described the attacker needs to have physical access to the DSL wire.