A new malware script surfaced on Friday that used a SQL injection attack to infect about 1,000 web pages with a malicious iFrame. The attack was a variation on last week's robint-us SQL mass infection, which similarly infected an estimated 7,000 Web pages.

Affected sites this time included the websites of Ameristar Casinos, Chicago's WBEZ public radio station, the Service Women's Action Network (for the second time), IndustryWeek, the European platform for food sovereignty, and Spain-holiday. Some of those sites continue to be infected.

Malicious iFrame attacks embed a malicious script in a web page, causing it to connect to a feeder site and download further malicious code. Different attacks then take different tacks, with the script either exploiting a browser vulnerability to run the malicious code automatically, or else attempting to trick a user into running it.

The new malware script points to http://2677.in/yahoo.js. According to security firm Sucuri, the attack script "loads malware from http://2677.in/ie.html, which then calls http://s11.cnzz.com to load the virus."

Symantec dubs that virus "HTTP Microsoft IE Generic Heap Spray BO," which targets a buffer overflow present either in the browser or an Internet Explorer ActiveX control. According to Symantec, "successfully exploiting this issue allows remote attackers to execute arbitrary code in the context of the application." On the Firefox browser, however, a successful attack would not execute code, but might result in a denial of service.

The attacks have targeted IIS machines, and also "targeted ASP.NET web applications vulnerable to SQL injection and using SQL server as database," according to researchers at Armorize Technologies. But, they said, vulnerabilities in the Web applications running on the servers -- rather than IIS, the ASP.NET Web application framework or SQL server -- were at fault.

Furthermore, they said, the attacks don't appear to have been random. "Attack vectors used in [the] mass SQL injections were targeted and specific -- pre-scanning took place beforehand," giving attackers a shortlist of sites to hit when they began their zero-day attack, according to Armorize.

The previous attack, robint-us, was rendered moot after ShadowServer, a security group, "sinkholed" all calls back to the robint-us domain. As a result, according to a post on the group's website, "drive-by Web browsers will be unable to download the exploit code," even though infected sites "will still include a link to the original malicious code." In addition, by tracking website referral strings, Shadowserver said it was working to "provide alerts and reports back to the affected network owners."