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Five Lies and a Truth: Attacking the Defender's Dilemma

Five Lies and a Truth: Attacking the Defender's Dilemma

There’s an old saying in security: “Attackers only have to be right once; defenders have to be right every time”. We call this “the Defender’s Dilemma”, and many organizations have built their entire security programs around it. But the Defender’s Dilemma is based on a very narrow slice of the attack lifecycle: the initial point of entry. When you look at the full scope of both the attacker’s and the defender’s activity, you see that the assumptions underlying the Defender’s Dilemma are misleading at best, and often entirely wrong. In this presentation, we’ll examine each of those assumptions and demonstrate that they are untrue. In fact, defenders have many advantages that they often fail to realize, and by exploiting them we can create a beneficial situation known as “the Attacker’s Dilemma”.

By the end of this session, attendees will not only realize the fundamental untruths of the Defender’s Dilemma and their negative impacts on security, but also understand how the Attacker’s Dilemma can increase morale, raise attackers’ costs, and improve the security posture of their organizations.

David J. Bianco

December 09, 2021
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  1. © 2021, David J. Bianco
    Five Lies and a Truth
    Attacking the Defender’s Dilemma
    David J. Bianco
    [email protected]
    @DavidJBianco

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  2. SANS Instructor
    Principal Engineer,
    Cybersecurity
    Target Corporation
    Incident Detection &
    Response Researcher
    • The Pyramid of Pain
    • Threat Intelligence
    • Threat Hunting
    About Me

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  3. “Defenders have to get it right
    every time. Attackers only need to
    be right once.”
    3
    Defenders
    Attackers

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  4. 4

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  5. The Defender’s Dilemma is Actively Harmful
    5
    Wrong
    Premise
    Bad
    Decisions
    Wasted
    Resources
    Tired,
    Demoralized
    Defenders
    Bad Security
    Outcomes

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  6. Lie #1: Defense & Offense are Separate
    6
    When you detect an
    adversary’s use of a
    particular indicator and
    respond to it quickly, you
    force them to expend effort
    to replace it.
    By imposing cost, you turn
    a defensive program into
    an offensive one! https://bit.ly/PyramidOfPain

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  7. Lie #2: Defenders Must be On Duty 24/7
    7
    Kind of true… BUT!
    Automation and SOAR can mitigate the worst
    of this asymmetry.
    What is each side doing between attacks?
    • Attackers plan their next attacks
    • Defenders learn skills and improve
    defenses

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  8. Lie #3: Defenders Have to Play Fair
    8
    There’s no such thing as
    cheating for the Blue Team!
    Attackers have needs, goals
    and habits. Take advantage of
    them.
    Deception technology makes it
    quite easy to lie and cheat at
    scale.

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  9. Lie #4: You Can’t Defend Against 0-Days
    9
    An exploit is only a
    foothold. What comes
    after is the important bit.
    Look for exploits but
    concentrate on behaviors!
    MITRE ATT&CK is a great
    start for cataloging
    behaviors.

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  10. Lie #5: Defenders Have to Get it Right Every Time
    10
    Attacks are not single events.
    Attack lifecycle models imply
    structure and time.
    You have a lot of chances to detect
    the attacker over its entire lifetime!

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  11. The Truth: The Attacker’s Dilemma!
    11
    Defenders
    Attackers
    “Attackers have to get it right
    through the entire attack.
    Defenders only need to detect
    once.”

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  12. The Attacker’s Dilemma is Beneficial
    12
    Correct
    Premise
    Good
    Decisions
    Efficient Use
    of
    Resources
    Energized,
    Empowered
    Defenders
    Better
    Security
    Outcomes

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  13. A Throne of Lies
    13
    Defense & Offense are Separate
    Defenders Must be On Duty 24/7
    Defenders Have to Play Fair
    You Can’t Defend Against 0-Days
    Defenders Have to be Right Every Time. Attackers Only Have to
    be Right Once.

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  14. Attacking the Defender’s Dilemma
    Questions?
    David J. Bianco
    [email protected]
    @DavidJBianco

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