.Gov, .Mil URL-Shortener Spam Attack Curtailed

URL shorteners notoriously come with some risk as well as convenience, and attackers are now abusing the federal government's official link-shortening service, 1 usa.gov.

Researchers at Dell SecureWorks last week discovered a spam scam spoofing 1 usa.gov, with emails that included shortened URLs of legit agencies. Victims who clicked on the links were redirected to work-from-home scam websites. A surge in successful attacks hit on Oct. 18, but once the General Services Administration (GSA) stepped in and put up warning pages to users, the scam was derailed on Oct. 19, according to SecureWorks, which alerted GSA of the scam before going public with its research.

It's another example of how URL shorteners can be abused by the bad guys.

"The risks of URL shorteners for masking the destination site are well-known and have been abused in the past. The standout here is that the 1.usa.gov shortener is meant to be limited to .gov and .mil sites. As such, it's likely to be more trusted by end users. That seems to have been one of the design goals when it was first created," says Jeff Jarmoc, a senior security researcher with Dell SecureWorks' Counter Threat Unit. "In many ways, this is unfortunately common spamming activity. The major difference here is that the attackers were able to combine .gov sites with open redirect vulnerabilities with the 1.usa.gov URL shortener to produce short links which appear to direct to a .gov site, but instead direct to their own scam site."

SecureWorks saw some 20,000 clicks of the scam links between Oct. 12 and Oct. 16, but the biggest surge came on Oct. 18.

Jarmoc says while this spam campaign was not especially dangerous -- the spam messages were raw and relatively unsophisticated -- because it was relatively easy to spot as a phony. And the good news is that it didn't harbor any malware.

It was more of a foreshadowing of possible attacks. The issue is that .gov URLs can be created and pointed to non-.gov sites, Jarmoc says.

"If this technique were used in conjunction with a better crafted message that played up the .gov angle, such as the common IRS phishing scams, which seem to occur every year, it could make for a very convincing phish," he says. "There's also some risks of targeted attacks either against government employees, or those in corporate environments who routinely interact with government officials. So far, neither scenario appears to have played out."

The attackers were mainly searching for servers with an open-redirect vulnerability in DotNetNuke's LinkClick.aspx file. That allowed the attackers to redirect the victim to their sites while appearing to be via 1.usa.gov. The phony sites spoofed CNBC news pages, with content "scraped" from the legitimate CNBC.com site, according to SecureWorks' research.

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