A
True Story
One
morning a few years back, a group of strangers walked into
a large shipping firm and walked out with access to the firm's
entire corporate network. How did they do it? By obtaining
small amounts of access, bit by bit, from a number of different
employees in that firm. First, they did research about the
company for two days before even attempting to set foot on
the premises. For example, they learned key employees' names
by calling HR. Next, they pretended to lose their key to the
front door, and a man let them in. Then they "lost" their
identity badges when entering the third floor secured area,
smiled, and a friendly employee opened the door for them.
The
strangers knew the CFO was out of town, so they were able
to enter his office and obtain financial data off his unlocked
computer. They dug through the corporate trash, finding all
kinds of useful documents. They asked a janitor for a garbage
pail in which to place their contents and carried all of this
data out of the building in their hands. The strangers had
studied the CFO's voice, so they were able to phone, pretending
to be the CFO, in a rush, desperately in need of his network
password. From there, they used regular technical hacking
tools to gain super-user access into the system.
In this
case, the strangers were network consultants performing a
security audit for the CFO without any other employees' knowledge.
They were never given any privileged information from the
CFO but were able to obtain all the access they wanted through
social engineering. (This story was recounted by Kapil Raina,
currently a security expert at Verisign and co-author of mCommerce
Security: A Beginner's Guide , based on an actual workplace
experience with a previous employer.)
Definitions
Most
articles I've read on the topic of social engineering begin
with some sort of definition like "the art and science of
getting people to comply to your wishes" ( Bernz
2 ), "an outside hacker's use of psychological tricks
on legitimate users of a computer system, in order to obtain
information he needs to gain access to the system" ( Palumbo
), or "getting needed information (for example, a password)
from a person rather than breaking into a system" ( Berg
). In reality, social engineering can be any and all of
these things, depending upon where you sit. The one thing
that everyone seems to agree upon is that social engineering
is generally a hacker's clever manipulation of the natural
human tendency to trust. The hacker's goal is to obtain information
that will allow him/her to gain unauthorized access to a valued
system and the information that resides on that system.
Security
is all about trust. Trust in protection and authenticity.
Generally agreed upon as the weakest link in the security
chain, the natural human willingness to accept someone at
his or her word leaves many of us vulnerable to attack. Many
experienced security experts emphasize this fact. No matter
how many articles are published about network holes, patches,
and firewalls, we can only reduce the threat so much... and
then it's up to Maggie in accounting or her friend, Will,
dialing in from a remote site, to keep the corporate network
secured.
Target
and Attack
The
basic goals of social engineering are the same as hacking
in general: to gain unauthorized access to systems or information
in order to commit fraud, network intrusion, industrial espionage,
identity theft, or simply to disrupt the system or network.
Typical targets include telephone companies and answering
services, big-name corporations and financial institutions,
military and government agencies, and hospitals. The Internet
boom had its share of industrial engineering attacks in start-ups
as well, but attacks generally focus on larger entities.
Finding
good, real-life examples of social engineering attacks is
difficult. Target organizations either do not want to admit
that they have been victimized (after all, to admit a fundamental
security breach is not only embarrassing, it may damaging
to the organization's reputation) and/or the attack was not
well documented so that nobody is really sure whether there
was a social engineering attack or not.
As for
why organizations are targeted through social engineering
- well, it's often an easier way to gain illicit access than
are many forms of technical hacking. Even for technical people,
it's often much simpler to just pick up the phone and ask
someone for his password. And most often, that's just what
a hacker will do.
Social
engineering attacks take place on two levels: the physical
and the psychological. First, we'll focus on the physical
setting for these attacks: the workplace, the phone, your
trash, and even on-line. In the workplace, the hacker can
simply walk in the door, like in the movies, and pretend to
be a maintenance worker or consultant who has access to the
organization. Then the intruder struts through the office
until he or she finds a few passwords lying around and emerges
from the building with ample information to exploit the network
from home later that night. Another technique to gain authentication
information is to just stand there and watch an oblivious
employee type in his password.
Social
Engineering by Phone
The
most prevalent type of social engineering attack is conducted
by phone. A hacker will call up and imitate someone in a position
of authority or relevance and gradually pull information out
of the user. Help desks are particularly prone to this type
of attack. Hackers are able to pretend they are calling from
inside the corporation by playing tricks on the PBX or the
company operator, so caller-ID is not always the best defense.
Here's a classic PBX trick, care of the Computer
Security Institute : "'Hi, I'm your AT&T rep, I'm
stuck on a pole. I need you to punch a bunch of buttons for
me.'"
And
here's an even better one: "They'll call you in the middle
of the night: 'Have you been calling Egypt for the last six
hours?' 'No.' And they'll say, 'well, we have a call that's
actually active right now, it's on your calling card and it's
to Egypt and as a matter of fact, you've got about $2,000
worth of charges from somebody using your card. You're responsible
for the $2,000, you have to pay that...' They'll say, 'I'm
putting my job on the line by getting rid of this $2,000 charge
for you. But you need to read off that AT&T card number
and PIN and then I'll get rid of the charge for you.' People
fall for it." ( Computer
Security Institute ).
Help
desks are particularly vulnerable because they are in place
specifically to help , a fact that may be exploited
by people who are trying to gain illicit information. Help
desk employees are trained to be friendly and give out information,
so this is a gold mine for social engineering. Most help desk
employees are minimally educated in the area of security and
get paid peanuts, so they tend to just answer questions and
go on to the next phone call. This can create a huge security
hole.
The
facilitator of a live Computer Security Institute demonstration,
neatly illustrated the vulnerability of help desks when he
"dialed up a phone company, got transferred around, and reached
the help desk. 'Who's the supervisor on duty tonight?' 'Oh,
it's Betty.' 'Let me talk to Betty.' [He's transferred.] 'Hi
Betty, having a bad day?' 'No, why?...Your systems are down.'
She said, 'my systems aren't down, we're running fine.' He
said, 'you better sign off.' She signed off. He said, 'now
sign on again.' She signed on again. He said, 'we didn't even
show a blip, we show no change.' He said, 'sign off again.'
She did. 'Betty, I'm going to have to sign on as you here
to figure out what's happening with your ID. Let me have your
user ID and password.' So this senior supervisor at the Help
Desk tells him her user ID and password." Brilliant.
A variation
on the phone theme is the pay phone or ATM. Hackers really
do shoulder surf and obtain credit card numbers and PINs this
way. (It happened to a friend of mine in a large US airport.)
People always stand around phone booths at airports, so this
is a place to be extra cautious.
Dumpster
Diving
Dumpster
diving, also known as trashing, is another popular method
of social engineering. A huge amount of information can be
collected through company dumpsters. The
LAN Times listed the following items as potential security
leaks in our trash: "company phone books, organizational charts,
memos, company policy manuals, calendars of meetings, events
and vacations, system manuals, printouts of sensitive data
or login names and passwords, printouts of source code, disks
and tapes, company letterhead and memo forms, and outdated
hardware."
These
sources can provide a rich vein of information for the hacker.
Phone books can give the hackers names and numbers of people
to target and impersonate. Organizational charts contain information
about people who are in positions of authority within the
organization. Memos provide small tidbits of useful information
for creating authenticity. Policy manuals show hackers how
secure (or insecure) the company really is. Calendars are
great - they may tell attackers which employees are out of
town at a particular time. System manuals, sensitive data,
and other sources of technical information may give hackers
the exact keys they need to unlock the network. Finally, outdated
hardware, particularly hard drives, can be restored to provide
all sorts of useful information. (We'll discuss how to dispose
of all of this in the second installment in this series; suffice
it to say, the shredder is a good place to start.)
On-Line
Social Engineering
The
Internet is fertile ground for social engineers looking to
harvest passwords. The primary weakness is that many users
often repeat the use of one simple password on every account:
Yahoo, Travelocity, Gap.com, whatever. So once the hacker
has one password, he or she can probably get into multiple
accounts. One way in which hackers have been known to obtain
this kind of password is through an on-line form: they can
send out some sort of sweepstakes information and ask the
user to put in a name (including e-mail address - that way,
she might even get that person's corporate account password
as well) and password. These forms can be sent by e-mail or
through US Mail. US Mail provides a better appearance that
the sweepstakes might be a legitimate enterprise.
Another
way hackers may obtain information on-line is by pretending
to be the network administrator, sending e-mail through the
network and asking for a user's password. This type of social
engineering attack doesn't generally work, because users are
generally more aware of hackers when online, but it is something
of which to take note. Furthermore, pop-up windows can be
installed by hackers to look like part of the network and
request that the user reenter his username and password to
fix some sort of problem. At this point in time, most users
should know not to send passwords in clear text (if at all),
but it never hurts to have an occasional reminder of this
simple security measure from the System Administrator. Even
better, sys admins might want to warn their users against
disclosing their passwords in any fashion other than a face-to-face
conversation with a staff member who is known to be authorized
and trusted.
E-mail
can also be used for more direct means of gaining access to
a system. For instance, mail attachments sent from someone
of authenticity can carry viruses, worms and Trojan horses.
A good example of this was an AOL hack, documented by VIGILANTe
: "In that case, the hacker called AOL's tech support
and spoke with the support person for an hour. During the
conversation, the hacker mentioned that his car was for sale
cheaply. The tech supporter was interested, so the hacker
sent an e-mail attachment 'with a picture of the car'. Instead
of a car photo, the mail executed a backdoor exploit that
opened a connection out from AOL through the firewall."
Persuasion
The
hackers themselves teach social engineering from a psychological
point-of-view, emphasizing how to create the perfect psychological
environment for the attack. Basic methods of persuasion include:
impersonation, ingratiation, conformity, diffusion of responsibility,
and plain old friendliness. Regardless of the method used,
the main objective is to convince the person disclosing the
information that the social engineer is in fact a person that
they can trust with that sensitive information. The other
important key is to never ask for too much information at
a time, but to ask for a little from each person in order
to maintain the appearance of a comfortable relationship.
Impersonation
generally means creating some sort of character and playing
out the role. The simpler the role, the better. Sometimes
this could mean just calling up, saying: "Hi, I'm Joe in MIS
and I need your password," but that doesn't always work. Other
times, the hacker will study a real individual in an organization
and wait until that person is out of town to impersonate him
over the phone. According to Bernz
, a hacker who has written extensively on the subject,
they use little boxes to disguise their voices and study speech
patterns and org charts. I'd say it's the least likely type
of impersonation attack because it takes the most preparation,
but it does happen.
Some
common roles that may be played in impersonation attacks include:
a repairman, IT support, a manager, a trusted third party
(for example, the President's executive assistant who is calling
to say that the President okayed her requesting certain information),
or a fellow employee. In a huge company, this is not that
hard to do. There is no way to know everyone - IDs can be
faked. Most of these roles fall under the category of someone
with authority, which leads us to ingratiation. Most employees
want to impress the boss, so they will bend over backwards
to provide required information to anyone in power.
Conformity
is a group-based behavior, but can be used occasionally in
the individual setting by convincing the user that everyone
else has been giving the hacker the same information now requested,
such as if the hacker is impersonating an IT manager. When
hackers attack in such a way as to diffuse the responsibility
of the employee giving the password away, that alleviates
the stress on the employee.
When
in doubt, the best way to obtain information in a social engineering
attack is just to be friendly. The idea here is that the average
user wants to believe the colleague on the phone and wants
to help, so the hacker really only needs to be basically believable.
Beyond that, most employees respond in kind, especially to
women. Slight flattery or flirtation might even help soften
up the target employee to co-operate further, but the smart
hacker knows when to stop pulling out information, just before
the employee suspects anything odd. A smile, if in person,
or a simple "thank you" clenches the deal. And if that's not
enough, the new user routine often works too: "I'm confused,
(batting eyelashes) can you help me?"
Reverse
Social Engineering
A final,
more advanced method of gaining illicit information is known
as "reverse social engineering". This is when the hacker creates
a persona that appears to be in a position of authority so
that employees will ask him for information, rather than the
other way around. If researched, planned and executed well,
reverse social engineering attacks may offer the hacker an
even better chance of obtaining valuable data from the employees;
however, this requires a great deal of preparation, research,
and pre-hacking to pull off.
According
to Methods
of Hacking: Social Engineering , a paper by Rick Nelson,
the three parts of reverse social engineering attacks are
sabotage, advertising, and assisting. The hacker sabotages
a network, causing a problem arise. That hacker then advertises
that he is the appropriate contact to fix the problem, and
then, when he comes to fix the network problem, he requests
certain bits of information from the employees and gets what
he really came for. They never know it was a hacker, because
their network problem goes away and everyone is happy.
Conclusion
Of course,
no social engineering article is complete without mention
of Kevin Mitnick, so I'll conclude with a quote from him from
an article
in Security Focus : "You could spend a fortune purchasing
technology and services...and your network infrastructure
could still remain vulnerable to old-fashioned manipulation."
Stay tuned for Part II: Combat Strategies, which will look
at ways of combatting attacks by identifying attacks, and
by using preventative technology, training, and policies.
To read
Social Engineering, Part Two: Combat Strategies ,
click here
.
References
Ameritech
Consumer Information "Social Engineering Fraud,"
http://www.ameritech.com/content/0,3086,92,00.html
Anonymous
"Social engineering: examples and countermeasures from the
real-world," Computer Security Institute
http://www.gocsi.com/soceng.htm
Arthurs,
Wendy: "A Proactive Defence to Social Engineering," SANS Institute,
August 2, 2001.
http://www.sans.org/infosecFAQ/social/defence.htm
Berg,
Al: "Al Berg Cracking a Social Engineer," by, LAN Times Nov.
6, 1995.
http://packetstorm.decepticons.org/docs/social-engineering/soc_eng2.html
Bernz
1: "Bernz's Social Engineering Intro Page"
http://packetstorm.decepticons.org/docs/social-engineering/socintro.html
Bernz
2: "The complete Social Engineering FAQ!"
http://packetstorm.decepticons.org/docs/social-engineering/socialen.txt
Harl
"People Hacking: The Psychology of Social Engineering" Text
of Harl's Talk at Access All Areas III, March 7, 1997.
http://packetstorm.decepticons.org/docs/social-engineering/aaatalk.html
Mitnick,
Kevin: "My first RSA Conference," SecurityFocus, April 30,
2001
http://www.securityfocus.com/news/199
Orr,
Chris "Social Engineering: A Backdoor to the Vault,", SANS
Institute, September 5, 2000
http://www.sans.org/infosecFAQ/social/backdoor.htm
Palumbo,
John "Social Engineering: What is it, why is so little said
about it and what can be done?", SANS Institute, July 26,
2000
http://www.sans.org/infosecFAQ/social/social.htm
Stevens,
George: "Enhancing Defenses Against Social Engineering" SANS
Institute, March 26, 2001
http://www.sans.org/infosecFAQ/social/defense_social.htm
Tims,
Rick "Social Engineering: Policies and Education a Must" SANS
Institute, February 16, 2001
http://www.sans.org/infosecFAQ/social/policies.htm
Verizon
"PBX Social Engineering Scam" 2000
http://www.bellatlantic.com/security/fraud/pbx_scam.htm
VIGILANTe
"Social Engineering" 2001
http://www.vigilante.com/inetsecurity/socialengineering.htm
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