Advanced Persistent Threats
Setting up perimeter security
- By David Finger
- Feb 04, 2014
An Advanced Persistent Threat (APT) is a
piece of malware that is distinguished by
the sophistication of its code, the vectors
cybercriminals are choosing for attack and
the perseverance with which they’re going
after their targets. The nature and intention
of APTs are as diverse as their creators, but some common
components include being:
- Targeted and tailored toward a specific organization or set of
- developed (and even tested) to pass traditional security defenses;
- multi-stage to stay undetected for longer periods of time;
- in search of specific information and able to move within the
organization seeking it; and
- stage and then exfiltrate information.
Most concerning, today’s APTs elude most, if not all, traditional
antivirus and other threat prevention solutions currently
on the market. In fact, IDC anticipates that spending on specialized
threat analysis and protection solutions will grow from an
estimated $400 million in 2013 to $1.2 billion in 2017.
As a result, new approaches to detecting and mitigating APT
breaches have reached the market and are growing in popularity.
From anomaly detection on the network to forensics at the endpoint
and payload analysis (known as “the sandbox”) in between,
there is growing recognition that, based on traditional security
infrastructure, what you don’t know can hurt you.
The Rise of the Sandbox
One technology generating great interest is “sandboxing.” In the
simplest terms, sandboxing cordons off a runtime environment
that could be a full, desktop replica or a small, operational task.
Within that contained environment, unknown code is introduced,
and its activity is tracked and rated in order to safely determine
its validity or maliciousness. Businesses are inserting sandboxes
into their stacks today because traditional security infrastructure,
such as firewalls and AV clients, are largely focused on code attributes,
the object itself and the network traffic to deliver it.
What these traditional solutions are not able to do is actually see
what the malicious code is doing, at least not in real-time on production
Determining the Best Sandbox
for Your Environment
Currently, most sandboxing technologies can fit into five distinct
buckets. Organizations need to consider the pros and cons of each
before determining which type makes the most sense to deploy.
Bucket #1: A full Virtual Operating Environment (V/OE) executes
high risk by type—seemingly benign code in environments
designed to match the full stack from OS throughput, as far as
traditional security inspection is concerned.
Initial and subsequent activity is
logged, analyzed and assigned a risk rating.
In addition, given the emergence of
virtual machine (VM) evasion techniques
in attacks, corresponding evasion inspection
is built into the sandbox environment.
Pros to full V/OE:
- Closely resembles the product system,
without being the production system,
to avoid performance degradation;
- analyzes the full threat lifecycle, which
is especially helpful when the initial
code is a simple downloader; and
- can be highly aggressive in what it inspects,
without impacting productivity.
Cons to full V/OE:
- Processor intensive, often expensive on
premise and time consuming;
- vulnerable to VM-evasion, despite continued
anti-evasion mechanisms; and
- handled off-line, making it more a detection
than a protection approach.
Bucket #2: Code emulation performs
multi-platform analysis to read instruction
sets and simulate activity rather than
examine the execution of code across
configurations. Based on this simulation,
intended activity such as system changes,
exploit efforts, download sites and communication
destinations can be identified
and previously unknown due to detected
signature or heuristic analysis malware.
Pros to code emulation:
- Not dependent on operating environment/
- immunity from, and often recognition
of, many AV and VM evasion techniques;
- an efficient inspection process that can
be run inline, without introducing significant
Cons to code emulation:
- Inspection is limited to the initial object,
rather than all elements of the attack;
- usually returns a rating without providing
Bucket #3: Application containers are
primarily used on mobile devices as a way
to separate personal and business user
spaces. Additionally, certain applications
include a contained application-specific
space. In both cases, the technology segments
business-oriented applications from
other applications on the device and establishes
a “secure workspace.” For example,
mobile email or a mobile CRM application
may be cordoned off in an attempt
to keep it safe from whatever the end user
might do in the personal space.
Pros of application containers:
- Runs directly on device as an inline prevention
- isolates work applications and data
from personal ones.
Cons of application containers:
- Generally not secure from OS and other
attacks that can bypass the container
walls or application attacks from items
already within the container;
- greatly limits the availability of apps
and/or requires special app development
for use in the container; and
- can be a poor user experience that is
Bucket #4: Secure browsers allow certain
Web objects and activity to be held and
run in a contained environment before being
allowed to access the rest of the system.
The technology includes a rating feature for
suspect sites and is becoming a standard
feature on today’s most common browsers.
Pros to secure browsers:
- Deployed inline on the production device;
- addresses a very common malware delivery
mechanism: the Web.
Cons to secure browsers:
- Offers no protection from OS or application-
- often conservative in its rating; and
- can introduce a degree of latency.
Bucket #5: Task-based VMs, also
referred to as micro-VMs, generally sequester
all tasks from the system and OS
through application and browser levels
for comprehensive coverage. Practically
all individual activities are enacted in a
contained environment, judged and then
blocked or allowed to proceed.
Pros to task-based VMs:
- Deployed inline on the production device;
- provides “full stack” coverage.
Cons to task-based VMs:
- Adds significant performance impact
and latency; and
- an aggressive security setting can slow
devices considerably, but one that’s too
lenient will let threats through.
to the Next Level
What makes sandboxes most effective is
a multi-pronged approach that uses the
strengths of one to counter the weaknesses
of another. Organizations are encouraged
to leverage more than one approach,
especially techniques that may be built-in.
For example, combining code emulation
with a full Virtual Operating Environment
on one box can improve the efficiency and
immunity to evasion of emulation to detect
certain advanced threats inline. This
will reserve offline, full, OS sandboxing for
the most sophisticated threats, especially
multi-stage attacks whose maliciousness is
only evident later in the lifecycle.
As security technologies continue to
evolve from signatures to heuristics to reputation
to behavior analysis, and beyond,
they often do so in response to evolution
in the threat landscapes and cybercrime.
While there is no silver bullet or endgame
in sight, organizations need to assess
their tolerance for risk and determine
which baseline, be it firewall (VPN,
Web filtering and anti-malware); emerging
(IPS, application control, whitelisting,
DLP and encryption); or advanced
(anomaly detection, sandboxing and forensics
security technologies), are right
for them. The good news is that there
is a number of promising sandboxing
technologies available to examine activity
and complement traditional measures
focused on attributes.
In particular, organizations transitioning
to a next-generation firewall (NGFW),
which includes firewall, VPN, IPS, application
control and anti-malware, that add
a sandbox, have a unique advantage over
businesses that prefer to take a piecemeal
approach to network security. An NGFW
and sandbox deliver a powerful combination
that can help organizations reduce
their security risk by:
- Preventing access to, downloads from
and communication with websites, applications
and external servers based
on category, reputation and port/protocol
analysis, as well as identification
during virtual execution of code;
- identifying malicious code through the
use of file signatures, traffic patterns,
attribute heuristics, code emulation
and full virtual execution; and
- understanding today’s threats in terms
of their nature and broader scope to
remediate faster and improve security
across the board.
This article originally appeared in the February 2014 issue of Security Today.