The use of internet search engines to uncover
vulnerabilities for launching attacks will increase as malicious
hackers seek exploitable information, according to security
experts.
Hackers have long used search engines to parse through a
website's source code, seeking clues about what the site contains
and configuration information that may be useful in launching an
attack.
"People have discovered that they can make a really tight Google
query that comes back with results that show lots of
vulnerabilities at once," said Matt Fisher, an application security
analyst at SPI Dynamics. "The hackers are getting a bunch of
potential targets with one web search."
He said past software development practices for websites often
resulted in insecure code containing critical information. Hackers,
using a web browser and a search engine, frequently parse websites
looking for just such exposed nuggets of exploitable
information.
As examples, Fisher cited back-up files and source code stored
in clear text or as HTML files, embedded comments containing
passwords and database schemas.
"Any invalid file extension, or a file ending in .inc, .bak or
.old, will get source code," he said. "The issue is poor web
application security" and does not reflect on search engine
security practices, he added. "Developers are not taught secure
coding. They are taught functional and efficient coding, but not
security. There is simply a lack of awareness."
Web application vulnerabilities are not homogeneous, and every
website is unique, Fisher said. "You can't issue a patch for a web
application vulnerability. You've got to fix it yourself, and since
Port 80 must be open, firewalls won't protect this type of
vulnerability."
Google spokesman Nate Tyler declined to comment, citing the
silent period required by the US Securities and Exchange Commission
before the search engine company's pending initial public offering.
Spokesmen for Lycos and Yahoo did not return calls.
Hackers have compounded the problem by using search engines to
conceal their locations and complicate forensics, said Chris
Wysopal, vice-president of engineering at security assessment
company @stake.
"When you search for a particular vulnerability using a search
engine, the search engine pulls all the (targeted) files into the
search engine cache, which does not leave the hacker's IP address,
so it covers their tracks," Wysopal said.
White hat ethical hackers conducting penetration tests and
security assessments also commonly use search engines, he said.
The recent Mydoom.O worm targeted search engine caches seeking
e-mail addresses. Search engines would have to remove functionality
to try to thwart hackers exploiting their caches, Wysopal said.
This would not be feasible in today's competitive internet
marketplace, which relies on powerful search engines to parse
through the boundless information on the internet.
"If a search engine were to cut its functionality (to limit its
use by hackers), people would start using another search engine.
It's not the search engine's responsibility to make sure your
website is secure. It's the site owner's responsibility to make
sure these problems aren't there," Wysopal said.
"Attackers are getting more sophisticated, and part of that is
using tools like search engines," he said. "Search engines
definitely increase the power of the attacker, and I expect this
trend will continue.
"People also need to understand how attackers work. They are not
going after one particular site, typically, but they have a goal in
mind, such as stealing credit cards," Wysopal said.
"Search engines allow hackers to see if the site has anything
interesting to them. Almost anything can come down to a particular
text string that can give a big clue as to if the site is
vulnerable. Once you have source code for the application, it's a
lot easier to find an exploit," he said.
Mark Willoughby writes for Computerworld