misp-training/a.5-bis-decaying-indicators.../content.tex

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% DO NOT COMPILE THIS FILE DIRECTLY!
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\begin{frame}[t,plain]
\titlepage
\end{frame}
\begin{frame}
\frametitle{Outline of the presentation}
\begin{itemize}
\item Present the components used in MISP to expire IOCs
\item Present the current state of Indicators life-cycle management in MISP
\end{itemize}
\end{frame}
\section{Expiring IOCs: Why and How?}
\begin{frame}[fragile]
\frametitle{Indicators lifecycle - Problem Statement}
\begin{itemize}
\item {\bf Sharing information} about threats {\bf is crucial}
\item Organisations are sharing more and more
\end{itemize}
\vspace{1em}
Contribution by {\bf unique organisation} (\texttt{Orgc.name}) on MISPPriv:\\
\vspace{1em}
\begin{minipage}{0.45\textwidth}
\begin{tabular}{ll}
\hline
Date & Unique Org \\
\hline
2013 & 17 \\
2014 & 43 \\
2015 & 82 \\
2016 & 105 \\
2017 & 118 \\
2018 & 125 \\
2019-10 & 135 \\
\hline
\end{tabular}
\vspace{0.5em}
\end{minipage}
\begin{minipage}{0.5\textwidth}
\begin{lstlisting}
{
"distribution": [1, 2, 3]
}\end{lstlisting}
\end{minipage}
\end{frame}
\begin{frame}
\frametitle{Indicators lifecycle - Problem Statement}
\begin{itemize}
\item Various users and organisations can share data via MISP, multiple parties can be involved
\begin{itemize}
\item \textbf{Trust}, \textbf{data quality} and \textbf{relevance} issues
\item Each user/organisation have \textbf{different use-cases} and interests
\begin{itemize}
\item Conflicting interests: Operational security VS attribution
\end{itemize}
\end{itemize}
\item[] $\rightarrow$ Can be partially solved with \textit{Taxonomies}
\pause
\vspace{0.5cm}
\item Attributes can be shared in large quantities \small{(more than 12M on \texttt{MISPPRIV} - Sept. 2020)}
\begin{itemize}
\item Partial info about their \textbf{freshness} (\textit{Sightings})
\item Partial info about their \textbf{validity} (\textit{last\_seen})
\end{itemize}
\item[] $\rightarrow$ Can be partially solved with our \textit{Data model}
\end{itemize}
\begin{center}
MISP's \textit{Decaying model} combines the two
\end{center}
\end{frame}
\begin{frame}
\frametitle{Requirements to enjoy the decaying feature in MISP}
\begin{itemize}
\item Starting from \textbf{MISP 2.4.116}, the decaying feature is available
\item \textbf{Update} decay models and \textbf{enable} some
\item MISP Decaying strongly relies on \textit{Taxonomies} and \textit{Sightings}, don't forget to review their configuration
\end{itemize}
\vspace{0.7cm}
Note: The decaying feature has no impact on the information stored in MISP, it's just an \textbf{overlay} to be used in the user-interface and API
\end{frame}
\begin{frame}
\frametitle{\textit{Sightings} - Refresher (1)}
\textit{Sightings} add a \textbf{temporal context} to indicators.
\begin{itemize}
\item \textit{Sightings} can be used to represent that you saw the IoC
\item \textbf{Usecase:} Continuous feedback loop MISP $\leftrightarrow$ IDS
\end{itemize}
\begin{center}
\includegraphics[scale=1.00]{pics/sightings.png}
\end{center}
\end{frame}
\begin{frame}
\frametitle{\textit{Sightings} - Refresher (2)}
\textit{Sightings} add a \textbf{temporal context} to indicators.
\begin{itemize}
\item \textit{Sightings} give more credibility/visibility to indicators
\item This information can be used to {\bf prioritise and decay indicators}
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Taxonomies - Refresher (1)}
\includegraphics[width=1.00\linewidth]{pics/taxonomies.png}
\begin{itemize}
\item \textit{Taxonomies} are a simple way to attach a classification to an \textit{Event} or an \textit{Attribute}
\item Classification must be globally used to be efficient (or agreed on beforehand)
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Taxonomies - Refresher (2)}
\includegraphics[width=1.00\linewidth]{pics/taxonomy-admiralty-scale.png}
\begin{center}
$\rightarrow$ Cherry-pick allowed \textit{Tags}
\end{center}
\end{frame}
\begin{frame}
\frametitle{Taxonomies - Refresher (3)}
\begin{itemize}
\item Some taxonomies have a \texttt{numerical\_value}
\item Allows concepts to be used in an mathematical expression
\begin{itemize}
\item[$\rightarrow$] Can be used to prioritise IoCs
\end{itemize}
\end{itemize}
\vspace{0.5cm}
\begin{footnotesize}
\texttt{admirality-scale} taxonomy\footnote{\url{https://github.com/MISP/misp-taxonomies/blob/master/admiralty-scale/machinetag.json}}
\begin{columns}[T] % align columns
\begin{column}{.40\textwidth}
\begin{tabular}{|ll|}
\hline
\textbf{Description} & \textbf{Value}\\
\hline
Completely reliable & 100\\
Usually reliable & 75\\
Fairly reliable & 50\\
Not usually reliable & 25\\
Unreliable & 0\\
Reliability cannot be judged & 50\\
Deliberatly deceptive & 0\\
\hline
\end{tabular}
\end{column}%
\hfill%
\begin{column}{.48\textwidth}
\begin{tabular}{|ll|}
\hline
\textbf{Description} & \textbf{Value}\\
\hline
Confirmed by other sources & 100\\
Probably true & 75\\
Possibly true & 50\\
Doubtful & 25\\
Improbable & 0\\
Truth cannot be judged & 50\\
\hline
\end{tabular}
\end{column}%
\end{columns}
\end{footnotesize}
\end{frame}
\begin{frame}
\frametitle{Taxonomies - Refresher (3)}
\begin{footnotesize}
\texttt{admirality-scale} taxonomy\footnote{\url{https://github.com/MISP/misp-taxonomies/blob/master/admiralty-scale/machinetag.json}}
\begin{columns}[T] % align columns
\begin{column}{.40\textwidth}
\begin{tabular}{|ll|}
\hline
\textbf{Description} & \textbf{Value}\\
\hline
Completely reliable & 100\\
Usually reliable & 75\\
Fairly reliable & 50\\
Not usually reliable & 25\\
Unreliable & 0\\
Reliability cannot be judged & 50 \textbf{\color{red}?}\\
Deliberatly deceptive & 0 \textbf{\color{red}?}\\
\hline
\end{tabular}
\end{column}%
\hfill%
\begin{column}{.48\textwidth}
\begin{tabular}{|ll|}
\hline
\textbf{Description} & \textbf{Value}\\
\hline
Confirmed by other sources & 100\\
Probably true & 75\\
Possibly true & 50\\
Doubtful & 25\\
Improbable & 0\\
Truth cannot be judged & 50 \textbf{\color{red}?}\\
\hline
\end{tabular}
\end{column}%
\end{columns}
\end{footnotesize}
\vspace{0.5cm}
$\rightarrow$ Users can override tag \texttt{numerical\_value}
\end{frame}
\begin{frame}
\frametitle{Scoring Indicators: Our solution}
$$ \texttt{score}(\texttt{\tiny Attribute}) = \texttt{base\_score}(\texttt{\tiny Attribute, Model}) \;\;\bullet\;\; \texttt{decay}(\texttt{\tiny Model, time}) $$
\begin{itemize}
\item \texttt{base\_score}(\texttt{\tiny Attribute, Model})
\begin{itemize}
\item Initial score of the \textit{Attribute} only considering the context (\textit{Attribute's type}, \textit{Tags})
\end{itemize}
\vspace{1cm}
\item \texttt{decay}(\texttt{\tiny Model, time})
\begin{itemize}
\item Function composed of the \textbf{lifetime} and \textbf{decay speed}
\item Decreases the \texttt{base\_score} over time
\end{itemize}
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Scoring Indicators: Our solution}
$$ \texttt{score}(\texttt{\tiny Attribute}) = \texttt{base\_score}(\texttt{\tiny Attribute, Model}) \;\;\bullet\;\; \texttt{decay}(\texttt{\tiny Model, time}) $$
\begin{center}
\begin{tikzpicture}
\draw[->] (-1, 0) -- (4.5, 0) node[right] {$time$};
\draw[->] (0, -1) -- (0, 4.2) node[left] {$score$};
\node at (-1, 2.6) {\footnotesize base\_score};
\draw[scale=0.5, domain=0:8, smooth, variable=\y, blue] plot ({\y}, {5 * (1 - (\y/8)^(3.5))});
\end{tikzpicture}
\end{center}
\end{frame}
\section{Current implementation in MISP}
\begin{frame}
\frametitle{Implementation in MISP: \texttt{Event/view}}
\includegraphics[width=1.00\linewidth]{pics/decaying-event.png}
\begin{itemize}
\item \texttt{Decay score} toggle button
\begin{itemize}
\item Shows Score for each \textit{Models} associated to the \textit{Attribute} type
\end{itemize}
\end{itemize}
\end{frame}
\begin{frame}[fragile]
\frametitle{Implementation in MISP: API result}
\texttt{/attributes/restSearch}
\begin{lstlisting}
"Attribute": [
{
"category": "Network activity",
"type": "ip-src",
"to_ids": true,
"timestamp": "1565703507",
[...]
"value": "8.8.8.8",
"decay_score": [
{
"score": 54.475223849544456,
"decayed": false,
"DecayingModel": {
"id": "85",
"name": "NIDS Simple Decaying Model"
}
}
],
[...]
\end{lstlisting}
\end{frame}
\begin{frame}
\frametitle{Implementation in MISP: Objectives}
\begin{itemize}
\item \textbf{Automatic scoring} based on default values
\item \textbf{User-friendly UI} to manually set \textit{Model} configuration (lifetime, decay, etc.)
\item \textbf{Simulation} tool
\item Interaction through the \textbf{API}
\item Opportunity to create your \textbf{own} formula or algorithm
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Implementation in MISP: Models definition}
\hspace{190pt}
\raisebox{-1.0ex}{\Large $\Rsh$} {\tiny $score = base\_score \cdot \left( 1 - \left( \frac{t}{\tau} \right)^{\frac{1}{\delta}} \right) $}
\textit{Models} are an instanciation of the formula with configurable parameters:
\begin{itemize}
\item Parameters: \texttt{lifetime, decay\_rate, threshold}
\item \texttt{base\_score} computation
\item \texttt{default base\_score}
\item associate \textit{Attribute} types
\item formula
\item creator organisation
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Implementation in MISP: Models Types}
Two types of model are available
\begin{itemize}
\item \textbf{Default Models}: Created and shared by the community. Coming from \texttt{misp-decaying-models} repository\footnote{\url{https://github.com/MISP/misp-decaying-models.git}}.
\begin{itemize}
\item[$\rightarrow$] Not editable
\end{itemize}
\vspace{0.5cm}
\item \textbf{Organisation Models}: Created by a user on MISP
\begin{itemize}
\item Can be hidden or shared to other organisation
\item[$\rightarrow$] Editable
\end{itemize}
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Implementation in MISP: Index}
\includegraphics[width=1.00\linewidth]{pics/decaying-index.png}
Standard CRUD operations: View, update, add, create, delete, enable, export, import
\end{frame}
\begin{frame}
\frametitle{Implementation in MISP: Fine tuning tool}
\includegraphics[width=1.00\linewidth]{pics/decaying-tool.png}
Configure models: Create, modify, visualise, perform mapping
\end{frame}
\begin{frame}
\frametitle{Implementation in MISP: \texttt{base\_score} tool}
\includegraphics[width=1.00\linewidth]{pics/decaying-basescore.png}
Adjust Taxonomies relative weights
\end{frame}
\begin{frame}
\frametitle{Implementation in MISP: simulation tool}
\includegraphics[width=1.00\linewidth]{pics/decaying-simulation.png}
Simulate decay on \textit{Attributes} with different \textit{Models}
\end{frame}
\begin{frame}[fragile]
\frametitle{Implementation in MISP: API query body}
\texttt{/attributes/restSearch}
\begin{lstlisting}
{
"includeDecayScore": 1,
"includeFullModel": 0,
"excludeDecayed": 0,
"decayingModel": [85],
"modelOverrides": {
"threshold": 30
}
"score": 30,
}
\end{lstlisting}
\end{frame}
\lstset{language=PHP}
\begin{frame}[fragile]
\frametitle{Creating a new decay algorithm}
\lstset{basicstyle=\scriptsize}
\begin{lstlisting}
<?php
include_once 'Base.php';
class Polynomial extends DecayingModelBase
{
public const DESCRIPTION = 'The description of your new decaying algorithm';
public function computeScore($model, $attribute, $base_score, $elapsed_time)
{
// algorithm returning a numerical score
}
public function isDecayed($model, $attribute, $score)
{
// algorithm returning a boolean stating
// if the attribute is expired or not
}
}
?>
\end{lstlisting}
\end{frame}
\begin{frame}
\frametitle{Decaying Models 2.0}
\begin{itemize}
\item Improved support of \textit{Sightings}
\begin{itemize}
\item \texttt{False positive} \textit{Sightings} should somehow reduce the score
\item \texttt{Expiration} \textit{Sightings} should mark the attribute as decayed
\end{itemize}
\item Potential \textit{Model} improvements
\begin{itemize}
\item Instead of resetting the score to \texttt{base\_score} once a \textit{Sighting} is set, the score should be increased additively (based on a defined coefficient); thus \textbf{prioritizing surges} rather than infrequent \textit{Sightings}
\item Take into account related \textit{Tags} or \textit{Correlations} when computing score
\end{itemize}
\item Increase \textit{Taxonomy} coverage
\begin{itemize}
\item Users should be able to manually override the \texttt{numerical\_value} of \textit{Tags}
\end{itemize}
\end{itemize}
\end{frame}