Analyzing Android App Binaries - GDG Silicon Slopes Aug 2022

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Analyzing Android app binaries Pavlo Stavytskyi Google Developer Expert, Android

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■ Google Developer Expert, Android About me 2

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■ Google Developer Expert, Android ■ Mobile Infrastructure at Lyft About me 3

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4 Agenda

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■ Android package ﬁles Agenda 5

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■ Android package ﬁles ■ Reverse engineering Android apps Agenda 6

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7 Android package ﬁles

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■ .apk .aab .aar ﬁles Android package ﬁles 8

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■ .apk .aab .aar files ■ They are all .zip files Android package files 9

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10 Demo

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11 Reverse engineering Android apps

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■ APK Analyzer Reverse engineering Android apps 12

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■ APK Analyzer ■ dex2jar Reverse engineering Android apps 13

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■ APK Analyzer ■ dex2jar ■ JD-GUI Reverse engineering Android apps 14

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■ APK Analyzer ■ dex2jar ■ JD-GUI ■ Apktool Reverse engineering Android apps 15

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16 APK Analyzer

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17 Demo

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18 dex2jar

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■ brew install dex2jar dex2jar 19

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■ brew install dex2jar ■ d2j-dex2jar app-release.apk dex2jar 20

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■ brew install dex2jar ■ d2j-dex2jar app-release.apk ■ JD-GUI dex2jar 21

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22 Demo

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23 Apktool

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■ brew install apktool Apktool 24

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■ brew install apktool ■ apktool d app-release.apk Apktool 25

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■ brew install apktool ■ apktool d app-release.apk ■ Make a change Apktool 26

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■ brew install apktool ■ apktool d app-release.apk ■ Make a change ■ apktool b -f -d app-release Apktool 27

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■ keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000 Signing modiﬁed APK 28

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■ keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000 ■ jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.keystore app-release/dist/app-release.apk alias_name Signing modiﬁed APK 29