Download presentation

Presentation is loading. Please wait.

Published byNico Potter Modified over 3 years ago

1
Spam Deobfuscation Wissam Kazan Daniel Woods

2
Problem Description Example Spam Text: Get your Viagra pills here When Obfuscated: G3t y0u*r \/|aGrra Pi11z |-|eer Problem: Reverse Obfuscation so Spam Filters Work

3
Decoding G3t y0u*r \/|aGrra Pi11z |-|eer xxxxxxxxxxxxxxx?xxxxxxxxxxxxxxx Alignment G3t y0u*r \/|aGrra Pi11z |-|eer Get you-r V-iagr-a pills h--ere Solution Breakdown

4
Alignment Example Original Text: Wissam Obfuscated Text: VV|sS/\m Naive Alignment: Wissa--m EM Alignment: W-issa-m Correct Alignment: W-issa-m (Result 1.4% error at 37.7% obfuscation)

5
Example: G3t y0u*r \/|aGrra Pi11z |-|eer Maximum Likelihood HMM (Viterbi) G -> e -> t -> _ -> y –> o ->... | | | G 3 t _ y 0... Decoding Approaches Get y xx?xx Get y xx?xx Get_y xx?xx Get y xx?xx

6
Results (37.7% Obfuscation)

7
Example Result Obfuscated Text: a"bbove diGs{lqaiim3rss and+ e+XclAusXi70Nsd may nQoSt Apxply Correct Test: above disclaimers and exclusions may not apply HMM Prediction: abbove dislaimerss and tclusiond may not pply

Similar presentations

OK

Hidden Markov Model 11/28/07. Bayes Rule The posterior distribution Select k with the largest posterior distribution. Minimizes the average misclassification.

Hidden Markov Model 11/28/07. Bayes Rule The posterior distribution Select k with the largest posterior distribution. Minimizes the average misclassification.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on solar system free download Ppt on power crisis in india Ppt on first conditional worksheets Ppt on case study of cyber crime Ppt on red planet mars Ppt on cross cultural differences Ppt on biodegradable and non biodegradable trash Ppt on db2 introduction to logic Free download ppt on brain machine interface Writing process elementary ppt on cells