Description
Can you handle APKs? Download the android apk here.
Setup
APK unpacking
Download mobpsycho.apk and unzip it in a separate directory (APK unzip dumps lots of files).
Use strings/grep to hunt for "flag" within res/.
wget https://artifacts.picoctf.net/c_titan/53/mobpsycho.apk && \
mkdir mobpsycho && cd mobpsycho && \
unzip ../mobpsycho.apk
Solution
- Step 1Find the flag filestrings * | grep flag or ls -R | grep flag -B 20 shows res/color/flag.txt.strings * | grep flag
- Step 2Decode the hexflag.txt contains hex; pipe it through xxd -r -p (or CyberChef's From Hex) to recover the ASCII flag.cat res/color/flag.txt | xxd -r -p
Flag
picoCTF{ax8mC0RU6ve_NX85l4ax8mCl_a3e...}
The decoded hex string inside res/color/flag.txt is the flag.