Two Vendors Deny XSS Flaws

Two security vendors whose Websites were alleged by hackers to have cross-site scripting (XSS) vulnerabilities last week now say their sites don't have XSS flaws.

Acunetix and F5 this week said their sites were inaccurately cited with XSS flaws by the hacker bulletin board, Sla.ckers.

Tamara Borg, Acunetix's marketing director, says the company has no XSS or other vulnerabilities on its site. "We are developers of a Web application security software tool which detects such vulnerabilities," she says. "Our Website is scanned on a daily basis to ensure that no such vulnerabilities exist."

F5 says its site did have a vulnerability, but it was an HTML injection issue, not XSS. "With the vulnerability on our site, a specially crafted URL could cause an error page," says Ken Salchow, product marketing manager for F5. "But it would not run the code" like an XSS exploit would do, he says.

"It allows a hacker to throw up an error page with his text on it with funny messages," for example, Salchow says. "But it wasn't enabling hackers to download and execute code on unsuspecting computers and propagate."

A member of the Sla.ckers site concurred that F5's flaw was posted as an HTML injection flaw, but that "HTML injection is only a stone's throw from being XSS." But the hacker who posted the Acunetix site link says the link was tested and did indeed include the XSS flaw (it appears to have since been fixed). He says he has also now found another Acunetix link with an XSS flaw, which he will be posting today.

XSS and HTML injection are indeed closely related, says Jeremiah Grossman, CTO of White Hat Security. "The terms are often used interchangeably, with HTML injection being more severe," he says. "For instance, the exploit used in the Samy worm was HTML injection."

F5's Salchow says the HTML injection flaw didn’t infect any computers or permanently deface its site. "It would have been embarrassing if this had a wide distribution, or if the attackers had said some really bad things about us" or something. And it was an easy fix for F5, he says.

Meanwhile, the site is still actively posting XSS vulnerabilities. "What the posters on Sla.ckers.org have shown is they definitely know what XSS is and how to find it," Grossman says. Among the more notable new additions: Microsoft, Yahoo, Altavista, Apple, security standards organization ISC2, Verizon, T-Mobile, and CNN.

"We are all just doing this on the side," says "Kyran," a member of Sla.ckers group. "There is no targeted or unified effort. Rather scary isn't it? A small group of people doing this in their spare time, finding so many XSS vulns. It really makes you wonder what the real bad guys are doing."

— Kelly Jackson Higgins, Senior Editor, Dark Reading