REVERSE-PRACTICE-BUUCTF-3

reverse3

exe program, no shell, use ida to analyze. The
function window on the left finally finds the main function, F5 disassembles

base64 first, then adds the corresponding subscripts in order, and finally compares, writes the inverse script to get the flag

Different flag

exe program, no shell, ida analysis.
Find the main function in the left function window, F5 disassembles, and analyzes it as a maze. It can be seen that 1-up, 2-down, 3-left, 4-right

determine that the maze is 5*5 and cannot be touched To "1", finally to "#", the input number sequence is the flag.

The maze is relatively simple, so I walked on my own.

SimpleRev

elf file, no shell, ida analysis. The
main function logic is clear. Enter d or D into the Decry() function.
First analyze the content before the input, get the text and key strings, and convert all the keys to lowercase

and then input You can see in the red box that whether the input is uppercase or lowercase, the processing of the input is the same.

Write a script to get the flag. Note the length of the flag, and the submission is successful when the flag is all uppercase.

Java reverse decryption

.class file, open the analysis by jadx-jui. The
red box is the processing and verification of the input. The processing of the input is to add'@' sequentially, and then

write the reverse script in XOR 32 to get the flag