Workforce Mobility = More Shoulder Surfing Risk

An individual recently alerted me to an instance of sensitive information being displayed on an application screen in the context of limited or non-existent business value. There are a few key risk management issues here – if we ship data to a user’s screen there is a chance that:

  • it will be intercepted by unauthorized parties,
  • unauthorized parties will have stolen credentials and use them to access that data, and
  • unauthorized parties will view it on the authorized-user’s screen.

Today I am most interested in the last use case — where traditional and non-traditional “shoulder surfing” is used to harvest sensitive data from user’s screens.

In global financial services, most of us have been through periods of data display “elimination” from legacy applications. In the last third of the 20th century United States, individual’s ‘Social Security Numbers’ (SSN) evolved into an important component of customer identification. It was a handy key to help identify one John Smith from another, and to help identify individuals whose names were more likely than others to be misspelled. Informtation Technology teams incorporated SSN as a core component of individual identity across the U.S. across many industries. Over time, individual’s SSNs became relatively liquid commodities and helped support a broad range of criminal income streams. After the turn of the century regulations and customer privacy expectations evolved to make use of SSN for identification increasingly problematic. In response to that cultural change or to other trigger events (privacy breach being the most common), IT teams invested in large scale activities to reduce dependence on SSNs where practical, and to resist SSN theft by tightening access controls to bulk data stores and by removing or masking SSNs from application user interfaces (‘screens’).

For the most part, global financial services leaders, application architects, and risk management professionals have internalized the concept of performing our business operations in a way that protects non-public data from ‘leaking’ into unauthorized channels. As our business practices evolve, we are obligated to continuously re-visit our alignment with data protection obligations. In software development, this is sometimes called architecture risk analysis (an activity that is not limited to formal architects!).

Risk management decisions about displaying non-public data on our screens need to take into account the location of those screens and the assumptions that we can reliably make about those environments. When we could depend upon the overwhelming majority of our workforce being in front of monitors located within workplace environments, the risks associated with ‘screen’ data leakage to unauthorized parties were often managed via line-of-sight constraints, building access controls, and “privacy filters” that were added to some individual’s monitors. We designed and managed our application user interfaces in the context of our assumptions about those layers of protection against unauthorized visual access.

Some organizations are embarked on “mobilizing” their operations — responding to advice that individuals and teams perform better when they are unleashed from traditional workplace constraints (like a physical desk, office, or other employer-managed workspace) as well as traditional workday constraints (like a contiguous 8, 10, or 12-hour day). Working from anywhere and everywhere, and doing so at any time is pitched as an employee benefit as well as a business operations improvement play. These changes have many consequences. One important impact is the increasing frequency of unauthorized non-public data ‘leakage’ as workforce ‘screens’ are exposed in less controlled environments — environments where there are higher concentrations of non-workforce individuals as well as higher concentrations of high-power cameras. Inadvertently, enterprises evolving toward “anything, anywhere, anytime” operations must assume risks resulting from exposing sensitive information to bystanders through the screens used by their workforce, or they must take measures to effectively deal with those risks.

The ever more reliable assumption that our customers, partners, marketers, and vendors feel increasingly comfortable computing in public places such as coffee shops, lobbies, airports and other types of transportation hubs, drives up the threat of exposing sensitive information to unauthorized parties.

This is not your parent’s shoulder surfing…
With only modest computing power, sensitive information can be extracted from images delivered by high-power cameras. Inexpensive and increasingly ubiquitous multi-core machines, GPUs, and cloud computing makes computing cycles more accessible and affordable for criminals and seasoned hobbyists to extract sensitive information via off-the-shelf visual analysis tools

This information exposure increases the risks of identity theft and theft of other business secrets that may result in financial losses, espionage, as well as other forms of cyber crime.

The dangers are real…
A couple years ago Michael Mitchell and An-I Andy Wang (Florida State University), and Peter Reiher (University of California, Los Angeles) wrote in “Protecting the Input and Display of Sensitive Data:”

The threat of exposing sensitive information on screen
to bystanders is real. In a recent study of IT
professionals, 85% of those surveyed admitted seeing
unauthorized sensitive on-screen data, and 82%
admitted that their own sensitive on-screen data could
be viewed by unauthorized personnel at times. These
results are consistent with other surveys indicating that
76% of the respondents were concerned about people
observing their screens, while 80% admitted that
they have attempted to shoulder surf the screen of a
stranger .

The shoulder-surfing threat is worsening, as mobile
devices are replacing desktop computers. More devices
are mobile (over 73% of annual technical device
purchases) and the world’s mobile worker
population will reach 1.3 billion by 2015. More than
80% of U.S. employees continues working after leaving
the office, and 67% regularly access sensitive data at
unsafe locations. Forty-four percent of organizations
do not have any policy addressing these threats.
Advances in screen technology further increase the risk
of exposure, with many new tablets claiming near 180-
degree screen viewing angles.

What should we do first?
The most powerful approach to resisting data leakage via user’s screens is to stop sending that data to those at-risk application user interfaces.

Most of us learned that during our SSN cleanup efforts. In global financial services there were only the most limited use cases where an SSN was needed on a user’s screen. Eliminating SSNs from the data flowing out to those user’s endpoints was a meaningful risk reduction. Over time, the breaches that did not happen only because of SSN-elimination activities could represent material financial savings and advantage in a number of other forms (brand, good-will, etc.).

As we review non-public data used throughout our businesses, and begin the process of sending only that required for the immediate use case to user’s screens, it seems rational that we will find lots of candidates for simple elimination.

For some cases where sensitive data may be required on ‘unsafe’ screens Mitchell, Wang, and Reiher propose an interesting option (cashtags), but one beyond the scope of my discussion today.

REFERENCES:
“Cashtags: Protecting the Input and Display of Sensitive Data.”
By Michael Mitchell and An-I Andy Wang (Florida State University), and Peter Reiher (University of California, Los Angeles)
https://www.cs.fsu.edu/~awang/papers/usenix2015.pdf

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