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San Francisco Symphony

Challenge
Who knew musicians could program? They put a flag inside /problems/sfs/sfs! But when I run the program, it’s not printing out the flag. Find the flag!

Solution

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$ ls -la /problems/sfs
drwxr-xr-x  2 root root 4096 Nov  4 01:02 .
drwxr-x--x 10 root root 4096 Nov  4 23:56 ..
-rwxr-xr-x  1 root root 8586 Nov  4 01:02 sfs
--wx--x--x  1 root root  166 Nov  4 01:02 sfs.c

Only root can see the source file, but strings helps us output

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$ strings sfs | grep easyctf
easyctf{w0aw_stor1ng_fl4gs_in_pla1nt3xt_i5_s0oper_s3cure}

Flag

$ strings sfs | grep easyctf easyctf{w0aw_stor1ng_fl4gs_in_pla1nt3xt_i5_s0oper_s3cure}