Secarmy CTF 2.0 junior walkthrough - team krypton

Secarmy CTF 2.0 is an entry level CTF in a jeopardy style for beginner to mid-level Cybersecurity enthusiasts. A total of 44 challenges were there and greater than 1500 people had participated, this was not a group event but individual, i ranked 20th in this CTF #krypton.

Here is a walktrough of these challenges, I was able to complete.

Welcome

Welcome challenges were fairly simple and needed to just visit or hit a particular service, there were 3 challenges in this category.

1. Welcome all : This one was the easiest, just had to submit the flag in from the description itself.

welcome challenge

2. Netcat : Just doing a netcat with give IP address revealed the flag

netcat challenge

flag : secarmy{W3lc0m3_T0_S3c4RmyC7F0x02}

3. Instafamous : This was the very old post from secarmy instagram account, the flag was in the description of post

insta famous challenge

flag : secarmy{w3lc0me_1n$t@\_f@m1ly}

Starters

These challenges were related to concepts like number systems, encryption, etc

1. “16+8”

flag : secarmy{Num3er_sys73m}

we have given two files with numbers in it

73 65 63 61 72 6d 79 7b
--------------------------------------------------------------------
116 165 155 63 145 162 137 163 171 163 67 63 155 175

as the name suggests the first part was hex and the second was octal so doing a simple conversion we got the flag.

2. Die basis

flag : secarmy{fl@g_1s\_\_th3_b@s3}

two files given :

********c2VjYXJteXtmbEBnXzFzXw==*******
 **********L52GQM27MJAHGM35*********

the first one was base64 and the second one was base32 encoded

3. Easy capture

flag : secarmy{h3r3_y0u_c@ptur3}

01110011 01100101 01100011 01100001 01110010 01101101 01111001 01111011 01101000 00110011 01110010 00110011 01011111 01111001 00110000 01110101 01011111 01100011 01000000 01110000 01110100 01110101 01110010 00110011 01111101

4. Image

flag : secarmy{th3_im@ge_s4ys_i7_a11}

doing a simple zsteg revealed the flag

image steganography challenge

5. Th3 G1f7

flag : secarmy{h3re_1s_th3_g1ft}

same thing again the flag was revealed by a zsteg

streganography | zsteg

Forensics

These challenges were mix of steganography, exif data, file headers, and others to illustrate the concepts in basically digital forensics.

1. its all in your head

flag : secarmy{h3ad3rs_t3ll_a_l0t}

a corrupted png file was given , i tried hexdump but the magic bytes were different from png so i changed them with hexedit which revealed the flag.

incorrect headers of PNG file

2. secret

flag : secarmy{ain’t_visible?}

a pdf with a username and a password hidden by asterisks after using pdftotext tool the flag was found

3. the confusion

flag : secarmy{WA3_I7_s0_c0nfu3ing}

flag was split and hidden in two images the first part was ROT13 and second was ROT47

3. the bin

flag : secarmy{PAST3_B1N_H@S_S0LUT10N}

here you have the flag :

61 48 52 30 63 48 4d 36 4c 79 39 77 59 58 4e 30 5a 57 4a 70 62 69 35 6a 62 32 30 76 54 45 30 35 63 57 56 33 64 57 6b 3d
--------------------------------------------------------------------
61 48 52 30 63 48 4d 36 4c 79 39 77 59 58 4e 30 5a 57 4a 70 62 69 35 6a 62 32 30 76 57 6d 52 71 54 6a 6

hex to text conversion gave two links of pastebin out of which the second one was working flag

4. Save them

flag : secarmy{PAST3_B1N_H@S_S0LUT10N}

Binary / Reversing

1. Stringy flag : secarmy{l00k_a7_th3_str1ng5!!}

as the name suggests i did strings on the elf which gave me some weird strings c2VjYXJtH eXtsMDBrH X2E3X3RoH M19zdHIxH bmc1ISF9H i tried base64 but it didn't worked then i removed the H at the end and it gave me flag

2. Smash it

flag : secarmy{sm@sh1ng_st@ck_1s_t00_much_fun}

here’s the binary

reversing binaries | Smash It

3. F-L-A-S-H flag: secarmy{7h1s_w45_345y_p34zy}

here’s the binary

reversing binaries | FLASH

4. backyard cow

flag : secarmy{d0y0u_l1k3_c0w_languag3\_\_\_?}

here’s the binary

on reversing it with radare2 gave me a link to google drive file which has moo written everywhere, then i decoded it with cow interpreter

reversing binaries | backyard cow

web

web challenges were easy one’s the flag’s were in source code, all are captured without using any other tool or intercepting.

1. prizes flag : secarmy{s0urc3_i5_n3ces5ary}

2. web_salad flag : secarmy{w3b_buck3t_3nc0un7er3d}

3. Cookie Bank

flag : secarmy{the\_$hy_c00kie_w1th1n}

4. silly mangolian 2.0

flag : secarmy{why*1s_th1s_m0ng0li@n*$uch\_@_f00l}

Interfacing a 16x2 LCD display with 8051 microcontrollers

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Keywords:
cybersecurity, ctfhacking