Symantec suspects bot in attacks on D-Link routers

Suspicious port scanning that's been tracked back to D-Link routers may mean a worm or bot is on the loose

Suspicious port scanning that's been tracked back to D-Link routers may mean a worm or bot is on the loose and infiltrating the popular brand's devices using a three-year-old vulnerability, security researchers at Symantec said Tuesday..

The security company issued a warning Monday night to customers of its DeepSight threat notification service saying that there were "reliable reports" of an in-the-wild worm or bot that was attacking, then installing itself, on D-Link routers. By Tuesday, however, Symantec had taken a step back.

"After looking into it further, we decided that that was a little misleading," said Oliver Friedrichs , a director of Symantec's security response team. "It's unconfirmed at this point. But we have definitely seen an increase in attack activity, and that activity appears to be coming from other D-Link devices."

In other words, although Symantec's researchers haven't gotten their hands on a worm or bot sample, all the evidence points in that direction. "We suspect that it's a bot," he said.

According to Friedrichs, the attacks against the D-Link routers begin with hackers scanning TCP port 23 for an active SNMP (Simple Network Management Protocol) service, a flaw that first showed up in D-Link router firmware in 2005. "It looks like they're exploiting the SNMP vulnerability to reset and reconfigure the administrative password on the routers," said Friedrichs, perhaps to conduct "drive-by pharming" attacks that change a router's settings so its users are unknowingly directed to bogus or malicious Web sites instead of the real URLs.

"Having port 23 open on the Internet-facing side is a bad idea in general," said Petko Petkov , a prolific penetration tester from the UK who, with a partner, Adrian Pastor, has published research on hacking routers. "But I guess this is due to the fact that the attacked devices have only one Ethernet port and users can unwillingly expose otherwise privileged services on the Internet."

Router vulnerabilities are up and attacks against routers are on the upswing -- especially attacks that target devices used by consumers and small businesses to create wireless networks, said Friedrichs. "Attackers are increasingly looking beyond the desktop," he said, for new places to install -- and hide -- their malware.

Petkov wasn't shocked to hear of Symantec's warning. "We're not surprised at all, as all embedded-device(s) we have tested so far are vulnerable to all kinds of interesting vulnerabilities," Petkov said in an e-mail Tuesday. Nor would creating a worm or bot Trojan be tough. "Anybody can code a worm which attacks routers on a massive scale quite easily. Most of the research information is out there, so it is a matter of putting the pieces of the puzzle together."

Friedrichs characterized the port 23 scanning activity Symantec is seeing as "moderate" and said the researchers will continue to investigate. He and his team, however, had not been able to verify that the vulnerability had been patched, and if so, when, or which specific models of D-Link's routers might be at risk.

D-Link officials did not respond to a call for comment.

For the moment, the best advice Friedrichs had for D-Link router owners is to make sure that the SNMP service was not exposed to the Internet.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.
Gregg Keizer

Gregg Keizer

Computerworld
Show Comments

Brand Post

Imou: At home with security

Modern living is all about functionality and security for everybody from the very young to the very old. With Imou anybody can enjoy smart life – the solution is at their fingertips.

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?