Introduction:
The common weakness in these hacks is the password. It’s
an artifact from a time when our computers were not
hyper-connected. Today, nothing you do, no precaution
you take, no long or random string of characters can stop a
truly dedicated and devious individual from cracking your
account. The age of the password has come to an end;
we just
haven’t realized it yet. Passwords are as old as
civilization. And for as long as they’ve existed, people
have been breaking them.
In 413 BC, at the height of the Peloponnesian War,
theAthenian general Demosthenes landed in Sicily
with5,000 soldiers to assist in the attack on Syracusae.
Things were looking good for the Greeks. Syracusae, a
key ally of Sparta, seemed sure to fall. But during a
chaotic nighttime battle at Epipole, Demosthenes’
forces were scattered, and while attempting to regroup
they began calling out their watchword, a prearranged
term that would identify soldiers as friendly. The
Syracusans picked up on the code and passed it quietly
through their ranks. At times when the Greeks looked too
formidable, the watchword allowed their opponents to
pose as allies. Employing this ruse, theundermatched
Syracusans decimated the invaders, and when the sun rose,
their cavalry mopped up the rest. It was a turning point in
the war.The first computers to use passwords were likely
those in MIT’s Compatible Time-Sharing System,
developed in 1961. To limit the time any one user could
spend on the system, CTSS used a login to ration access.
It only took until 1962 when a PhD
student named Allan Scherr, wanting more than his fourhour
allotment, defeated the login with a simple hack: He
located the file containing the passwords and printed out
all of them. After that, he got as much time as he wanted.
During the formative years of the web, as we all went
online, passwords worked pretty well. This was due
largely to how little data they actually needed to protect.
Our passwords were limited to a handful of
applications: an ISP for email and maybe an ecommerce
site or two. Because almost no personal information was
in the cloud—the cloud was barely a wisp at that point
—there was little payoff for breaking into an
individual’s accounts; the serious hackers were still
going after big corporate systems.
So we were lulled into complacency. Email addresses
morphed into a sort of universal login, serving as our
username just about everywhere. This practice persisted
even as the number of accounts—the number of failure
points—grew exponentially. Web-based email was the
gateway to a new slate of cloud apps. We began banking
in the cloud, tracking our finances in the cloud, and doing
our taxes in the cloud. We stashed our photos, our
documents, our data in the cloud.
Eventually, as the number of epic hacks increased, we
started to lean on a curious psychological crutch: the
notion of the “strong” password. It’s the compromise that
growing web companies came up with to keep people
signing up and entrusting data to their sites. It’s the BandAid
that’s now being washed away in a river of blood.
One proposal to reduce problems related to text passwords
is to use password managers. These typically require that
users remember only a master password. They store (or regenerate)
and send on behalf of the user, to web sites
hosting user accounts, the appropriate passwords. Ideally
the latter are generated by the manager itself and are
stronger than user-chosen passwords. However,
implemen-tations of password managers introduce their
own usability issues [Chiasson et al. 2006] that can
exacerbate security problems, and their centralized
90 IJCSNS International Journal of Computer Science and Network Security, VOL.14 No.8, August 2014
architecture in-troduces a single point of failure and
attractive target: attacker access to the master password
provides control over all of the user’s managed accounts.
When text password users resort to unsafe coping
strategies, such as reusing pass-words across accounts to
help with memorability, the decrease in security cannot be
addressed by simply strengthening, in isolation, the
underlying technical secu-rity of a system. Usability issues
often significantly impact its real-world security. User
interface design decisions may unintentionally sway user
behaviour towards less secure behaviour. Successful
authentication solutions must thus also include improved
usability design based on appropriate research taking
into account the abilities and limitations of the target
users. In graphical passwords, human mem-ory for visual
information is leveraged in hope of a reduced memory
burden that will facilitate the selection and use of more
secure or less predictable passwords, dissuading users
from unsafe coping practices.
Early surveys of graphical passwords are available
[Monrose and Reiter 2005; Suo et al. 2005]. More
recent papers briefly summarize and categorize 12
schemes [Hafiz et al. 2008], and review numerous
graphical password systems while offering usability
guidelines for their design [Renaud 2009a]. In this
paper we provide a comprehensive review of the first
twelve years of published research on graphical passwords,
and reflect on it. It is now clear that the graphical nature of
schemes does not by itself avoid the problems typical of
text password systems. However, while proposals in this
first period of research exhibit some familiar problems, we
see signs that an emerging second generation of research
will build on this knowledge and leverage graphical
elements in new ways to avoid the old problems.
As will be seen, early graphical password systems tended
to focus on one par-ticular strength, for example being
resistant to shoulder-surfing, but testing and analysis
showed that they were vulnerable to one or more other
types of attacks. Except in very specific environments,
these would not provide adequate security.
Security:
An authentication system must provide adequate security
for its intended environ-ment, otherwise it fails to meet its
primary goal. A proposed system should at minimum be
evaluated against common attacks to determine if it
satisfies security requirements. A brief introduction is
provided here
We classify the types of attacks on knowledge-based
authentication into two general categories: guessing and
capture attacks. In successful guessing attacks,
attackers are able to either exhaustively search through the
entire theoretical pass-word space, or predict higher
probability passwords (i.e., create a dictionary of likely
passwords) so as to obtain an acceptable success rate
within a manageable number of guesses. Guessing attacks
may be conducted online through the intended login
interface or offline if some verifiable text [Gong et al.
1993] (e.g., hashes) can be used to assess the correctness
of guesses. Authentication systems with small the-oretical
password spaces or with identifiable patterns in user
choice of passwords are especially vulnerable to guessing
attacks.
Password capture attacks involve directly obtaining the
password, or part thereof, by capturing login credentials
when entered by the user, or by tricking the user into
divulging their password. Shoulder-surfing, phishing, and
some kinds of malware are three common forms of
capture attacks. In shoulder-surfing, credentials are captured
by direct observation of the login process or through
some external recording device such as a video camera.
Phishing is a type of social engineering attack where users
are tricked into entering their credentials at a fraudulent
website that records users’ input. Malware uses
unauthorized software installed on client computers or
servers to capture keyboard, mouse, or screen output,
which is then parsed to find login credentials.