# Securinet Little Baby Rev Write Up
## Details:
Jeopardy style CTF
Category: Reverse Engineering
## Write up:
Running the file we see that we are in an infinite loop:
```./warmup I have a number from 1 to 10, what is it? 2Try againI have a number from 1 to 10, what is it? 6```
Looking for these strings in the binary does not prove useful at all either but when I ctrl-c'd I noticed that it seemed to be running in a .nim file:
```Try againI have a number from 1 to 10, what is it? ^CTraceback (most recent call last)/root/rev/warmup.nim(39) warmup/root/Nim/lib/system/io.nim(491) readLine```
Instead of going down the rabbit hole of trying to figure out what nim is I decided to do some dynamic analysis.
I found the following function which seemed to be the while loop that I wanted:
```c while ( 1 )  {    v5 = 38LL;    v6 = "/root/rev/warmup.nim";    nimZeroMem_0(&v10, 8LL);    v10 = decodeStr__R9b5IlyQjG2mcdkp9a67LGTQ((__int64)&TM__ijE9cayl8YPnol3rizbiT0g_5, 0x3F1997CCu);    echoBinSafe(&v10, 1LL);    asgnRef_1(&guess__62AlRyOQv9cCViqvgI14ssA, 0LL);    v5 = 39LL;    v6 = "/root/rev/warmup.nim";    v1 = readLine__IfmAdseskhTUnfEYpOo5fA(stdin);    asgnRef_1(&guess__62AlRyOQv9cCViqvgI14ssA, v1);    v5 = 41LL;    v6 = "/root/rev/warmup.nim";    if ( (unsigned __int8)eqStrings(guess__62AlRyOQv9cCViqvgI14ssA, answer__2bKjAtEJJ5cp19bpmXcStjQ) )      break;    v5 = 42LL;    v6 = "/root/rev/warmup.nim";    nimZeroMem_0(&v9, 8LL);    v9 = decodeStr__R9b5IlyQjG2mcdkp9a67LGTQ((__int64)&TM__ijE9cayl8YPnol3rizbiT0g_7, 0x2149F624u);    echoBinSafe(&v9, 1LL);  }```
After reading in my string it compared it against the answer__2bKjAtEJJ5cp19bpmXcStjQ so I took a look at that memory while the program was running.
I saw that that contained:
```7FD1C85020A0```
And decided to look at the memory that this pointed to where I saw the following:
``` 53 65 63 75 72 69 6E 65  74 73 7B 4E 69 6D 70 65  Securinets{Nimpe 72 30 72 5F 54 68 65 5F  61 4E 69 6D 41 74 6F 72  r0r_The_aNimAtor 7D 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  }............... ```
 The flag was:
 ``` Securinets{Nimper0r_The_aNimAtor} ```