Tags: rev gdb
Rating:
# Call Me
File: [call_me](call_me)
Run the file:
```
# ./call_me
There is nothing...
Bye!
```
Running `strings`:
```
# strings call_me | grep Inno
/home/master/Documents/Projects/InnoCTF2019/Ural2018/Call me by my name
```
Running `readelf -s call_me` saw a function called `flag`:
```
# readelf -s call_me
66: 00000000000014f3 39 FUNC GLOBAL DEFAULT 13 main
67: 0000000000004040 0 OBJECT GLOBAL HIDDEN 23 __TMC_END__
68: 0000000000000000 0 NOTYPE WEAK DEFAULT UND _ITM_registerTMCloneTable
69: 0000000000001159 922 FUNC GLOBAL DEFAULT 13 flag
70: 0000000000000000 0 FUNC WEAK DEFAULT UND __cxa_finalize@@GLIBC_2.2
71: 0000000000001000 0 FUNC GLOBAL HIDDEN 11 _init
```
The challenge named `Call me` I guess we can call the function
After a quick google search, we found gdb can done [this](https://stackoverflow.com/questions/1354731/how-to-evaluate-functions-in-gdb)
```
# gdb call_me
...
...
pwndbg> break main
Breakpoint 1 at 0x1502: file var 2.c, line 20.
pwndbg> run
Starting program: /root/Downloads/InnoCTF2019/call_me/call_me
Breakpoint 1, main (argc=1, argv=0x7fffffffe188) at var 2.c:20
...
...
...
► f 0 555555555502 main+15
f 1 7ffff7e0809b __libc_start_main+235
Breakpoint main
pwndbg> call flag()
Your flag:
InnoCTF{How_d1d_y0u_f1nd_m3_7f1bc88}�
$1 = 39
```
# Flag
> InnoCTF{How_d1d_y0u_f1nd_m3_7f1bc88}
