CyberSecurity, AI and misc

CyberSecurity, AI and misc

CyberSecurity, AI and misc
Read more See more

Cybersecurity

[25] ASIS CTF Final Dec 2023 forensic challenge White & Blank 14 Janv 2024 ,v1.0 (en) [24] METARED November 2023 CTF : ARP spoofing challenge 29 Dec 2023,v1.0 (en) [23] Dragos 2023 CTF – Stegano...

ML/AI

[4] Notes sur les techniques de régularisation en machine Learning, Montréal, V1.0, Juin 2023, AA795, (fr), [PDF] [3] Norme et fonction norme de Frobenius, Montréal, V1.0, Avril 2023, AA805, (fr), [PDF] [2] Intelligence Artificielle et...

Misc

[48] QR Code Model 2 Structure and Algorithms, Montréal, Canada, Juin 2024 (v1.0), AB826, v1.0, (English), [PDF] [47] Treillis modulaire, Montréal, Canada, Mai 2023 (v1.0), AA823, v1.1, (french), [PDF] [46] Business Impact Analysis : skilled...

Cybersecurity

[25] ASIS CTF Final Dec 2023 forensic challenge White & Blank 14 Janv 2024 ,v1.0 (en)
[24] METARED November 2023 CTF : ARP spoofing challenge 29 Dec 2023,v1.0 (en)
[23] Dragos 2023 CTF – Stegano Writeup 05 Nov 2023,v1.0 (en)
[22] Implementation Security models Montréal, Canada, July 2023, P460, v1.0 (en)
[21] Kerberos V5 Montréal, Canada, Juillet 2023, Y760, v1.0 (en)[HTML][PDF]
[20] Activer MS Defender en powershell Montréal, Canada, Avril 2023, AA800, v1.0 (fr)
[19] Cracker une clé RSA-512 dans le contexte du ransomware Zeppelin Montréal, Canada, Avril 2023, Z791, v1.0 (fr)
[18] Contrôles d’accès basés sur treillis et modèles de sécurité, [HTML] Montréal, Canada, Décembre 2019, U638, v1.0 (fr)
[17] Clark-Wilson security model, Montréal, Canada, May 2019, U612, v1.0 (eng), [PDF]
[16] Brewer and Nash security model, Montréal, Canada, February 2019, P460.BN, v1.0 (eng), [PDF] [Semantic Scholar PDF]
[15] MD5 message-digest algorithm, Montréal, Septembre 2018, S562, (fr), [HTML][PDF]
[14] Process Doppelgänging, Montréal, Août 2018, R532, (fr), [PDF]
[13] Construction de Luby-Rackoff et réseaux de Feistel, Montréal, Juillet 2018, S548, (fr), [PDF]
[12] Statistical hypotheses (true positive, false negative etc…) and errors types, Montréal, Juillet 2018, S544, (en), [PDF]
[11] Méthodologies d’évaluation et gestion de risques en sécurité, Montréal, Mai 2018, R518, (fr), [PDF]
[10] Les réseaux de Feistel classiques et généralisés, Montréal, Février 2018, Q485, (fr), [PDF]
[09] Règles YARA : tests pratiques, Montréal, Novembre 2017, P455, (fr), [PDF]
[08] Sécurité Applicative et Security Developement Lifecycle : cheat sheet , Montréal, Octobre 2017, N420, (fr;en), [PDF]
[07] Règles YARA pour la détection de champ DDE – Microsoft Word, Montréal, Octobre 2017, O425, (fr), [PDF]
[06] GPG et chiffrement de fichiers, Montréal, Fév 2017, G192, [fr], [PDF]
[05] Analyse de risque quantitative en sécurité, Montréal, Oct 2016, G210, [fr], [PDF]
[04] La pyramide de stratégie de sécurité, Montréal, Oct 2016, H222, [fr], [PDF]
[03] IT: Disaster Recovery definitions, Montréal, Oct 2016, H226, [en], [PDF]
[02] Intelligible Obfuscation – An ITAF 3rd Audit Framework’s Lingo conversion, Montréal, May 2016, D115, [en], [PDF]
[01] [Bibliographie] Les fondements juridiques de la sécurité de l’information au Québec et Canada, Montreal, Avril 2016, M372, [fr], [PDF]

Protected: Be

Protected: Be

This content is password protected. To view it please enter your password below: Password: Read More "Protected: Be"
ASIS CTF Final Dec 2023 : challenge White & Blank Writeup

ASIS CTF Final Dec 2023 : challenge White & Blank Writeup

ASIS organized in December 2023 the ASIS CTF Final 2023.  I detail here my writeup for the challenge "White & Blank". The challenge was "Dive into... Read More "ASIS CTF Final Dec 2023 : challenge White & Blank Writeup"
METARED November 2023 CTF : ARP spoofing challenge

METARED November 2023 CTF : ARP spoofing challenge

MetaRed TIC Ecuador was  responsible for organizing  the 5th stage of the MetaRed International CTF (Capture the Flag) 2023. The first challenge, named "ARP Spoofing... Read More "METARED November 2023 CTF : ARP spoofing challenge"
DRAGOS CTF 2023 – Stegano Writeup

DRAGOS CTF 2023 – Stegano Writeup

DRAGOS CTF 2023 After some easy trivia challenges in the DRAGOS 2023 CTF, the first 200 points challenge, called "Global Session planning" was a stegano... Read More "DRAGOS CTF 2023 – Stegano Writeup"

ML/AI

[4] Notes sur les techniques de régularisation en machine Learning, Montréal, V1.0, Juin 2023, AA795, (fr), [PDF]

[3] Norme et fonction norme de Frobenius, Montréal, V1.0, Avril 2023, AA805, (fr), [PDF]

[2] Intelligence Artificielle et réseaux neuronaux, Montréal, V1.2 Avril 2023, Z766, (fr), [PDF]

[1] Fonctions de coûts et Machine Learning, Montréal, Janvier 2018, Q489, (fr), [PDF]

Protected: Be

Protected: Be

This content is password protected. To view it please enter your password... Read More "Protected: Be"
ASIS CTF Final Dec 2023 : challenge White & Blank Writeup

ASIS CTF Final Dec 2023 : challenge White & Blank Writeup

ASIS organized in December 2023 the ASIS CTF Final 2023.  I detail here... Read More "ASIS CTF Final Dec 2023 : challenge White & Blank Writeup"
METARED November 2023 CTF : ARP spoofing challenge

METARED November 2023 CTF : ARP spoofing challenge

MetaRed TIC Ecuador was  responsible for organizing  the 5th stage of the... Read More "METARED November 2023 CTF : ARP spoofing challenge"
DRAGOS CTF 2023 – Stegano Writeup

DRAGOS CTF 2023 – Stegano Writeup

DRAGOS CTF 2023 After some easy trivia challenges in the DRAGOS 2023... Read More "DRAGOS CTF 2023 – Stegano Writeup"
Security models Cheat sheet

Security models Cheat sheet

Information Security models (security architecture implemenations models) Franck Jeannot - July 2023... Read More "Security models Cheat sheet"
Kerberos V5 attacks

Kerberos V5 attacks

Franck Jeannot Montréal, Canada, July 2023, Y760, v1.0.  Article complet [PDF] Abstract This... Read More "Kerberos V5 attacks"

Misc

[48] QR Code Model 2 Structure and Algorithms, Montréal, Canada, Juin 2024 (v1.0), AB826, v1.0, (English), [PDF]
[47] Treillis modulaire, Montréal, Canada, Mai 2023 (v1.0), AA823, v1.1, (french), [PDF]
[46] Business Impact Analysis : skilled worker’s knowledge review , Montréal, Canada, Mai 2023, AA816, v1.0, (english), [PDF]
[45] Über Matrizen aus positiven Elementen, (Von G. Frobenius.
Göttingen : Königliche Gesellschaft der Wissenschaften, 1908; Société Royale des Sciences) Mai 2023, AA815, [german, french] , [PDF]
[44] Loi de Benford et généralisations, Montréal, Avril 2023, AA801, [french] , [PDF]
[43] Loi de Benford et implémentation python, Montréal, Avril 2023, AA799, [fr], [PDF]
[42] Île Rock et Justicia americana – Montréal, Montréal, Décembre 2019, V671, [fr], [PDF]
[41] Expérimentations sur la loi de Benford, Montréal, Août 2017, C82, [fr], [PDF]
[40] La Yougoslavie en 1989, Montréal, Juillet 2017, M382, [fr], [PDF]
[39] Le cadre d’architecture d’entreprise Zachman, Montréal, Mars 2017, I271, [fr], [PDF]
[38] Vectorisation stylisée de dessins d’un manuscrit copte du 14ème siècle par Algorithme de tracing, Montréal, Février 2017, I259, [fr], [PDF]
[37] La migration du papillon Monarque Danaus plexippus, Montréal, Janvier 2017, G191, [fr], [PDF]
[36] Histoire du baguenaudier, Montréal, Décembre 2016, E133, [fr], [PDF]
[35] Unix / Linux cheat sheet : differences examples, Montréal, Nov 2016, H227, [en-fr], [PDF]
[34] IT: Disaster Recovery definitions, Montréal, Oct 2016, H226, [en], [PDF]
[33] Apache for Linux configuration Guide, Montréal, Sept 2016, G185, [en], [PDF]
[32] Domain Name Server for the LPIC, Montréal, Juillet 2016, F158, [en], [PDF]
[31] Teaser pour roman : Le Maruti Corse – V1.2, Montréal, Juin 2016, A20, [fr], [PDF]
[30] Les systèmes à réaction-diffusion , Montréal, May 2016, D118, [fr], [PDF]
[29] Un récif corallien en Amazonie!, Montréal, Juin 2016, F164, [fr], [PDF]
[28] Armoire chinoise en orme laqué noir, laiton et pierres en applique, Montreal, Paris, 2016, [fr], [PDF]
[27] Hippocampe pygmée des gorgones (Hippocampus bargibanti), Canada, Montreal, Janvier 2016, [fr], [PDF]
[26] PMP – Project Management Professional Formulas, Canada, Montreal, May 2015, [en], [PDF]
[25] Mexico – Isla mujeres : belles photos, Mexico, May 2015, [en], [PDF]
[24] Capacity planning and queueuing theory, Canada, Montreal, April 2015, A04, [en], [PDF]
[23] Antminer U2 V1.2 ASIC Bitcoins Hash BM1380 test, Canada, Montreal, 2014, A06, [en], [PDF]
[22] Mexico – Huatulco : belles photos, Mexique, Huatulco, 2014, [en], [PDF]
[21] Costa Rica – Playa del Coco photos, Montréal, 2013, P467, [fr], [PDF]
[20] Halocynthia papillosa, Montreal, 2012 (photo 2005 Corsica), [en], [PDF]
[19] Canada Parks, Montreal, 2012, [en], [PDF]
[18] Mexico – Cozumel, Cozumel-Mexique, 2012, [fr], [PDF]
[17] Pêche aux petits poissons des Chenaux, Canada, Montreal, 2012, [fr], [PDF]
[16] Recherche Opérationnelle : la loi de Little, France, Paris, 2011, [fr], [PDF]
[15] Photos BIO sous-marine Bretagne, France, 2010, A14 [fr], [PDF]
[14] Photos Niolon Stage BIO CODEP 75, France, Mai 2010, Q481 [fr], [PDF]
[13] Ecole d’Ingénieur par Apprentissage, France, 2010, A24 [fr], [PDF]
[12] Carcharhinus longimanus, Egypte, 2009, [fr], [PDF]
[11] Fishwatching – Expéditions Voyages Bio sous-marine , 2008-2010, [fr], [PDF]
[10] Sulawesi Voyage Bio sous-marine en Mer de Celebes, Indonésie centrale, Manado, 2008, A06, [fr],[PDF]
[09] Plongée sous-marine Sulawesi – Indonésie, 2008 [fr], [Sulawesi]
[08] Operation Akhilleus, Roman d’espionnage historique, France, Paris, ed. Le Manuscrit, 2006,ISBN 13: 9782748170009, 390 pages, A05 [fr], [PDF]
[07] Nautical Archeological Society Level 2 Report – Relevé de l’épave Puntalle, Corse, 2009, [fr], [PDF]
[06] Plongée et croisière Saint-John en Egypte, Egypte, 2007, A10, [fr], [PDF]
[05] LEOMARE : Robinetterie de plongée, DIN et étier, France, Paris, La Mare à Leo, 2005, [fr], [PDF]
[04] La recherche opérationnelle, France, Paris, 2004, B33 [fr], [PDF]
[03] Plongée exploration Camaret sur Mer 2003, France, 2003, B34, [fr], [PDF]
[02] Courses croisières EDHEC 1998 et 1999, France, Angoulême, 1999, C89, [fr], [PDF]
[01] Coupe de robotique E=M6, France, Angoulême, 1998, B41, [fr], [PDF]

DRAGOS CTF 2023 – Stegano Writeup

DRAGOS CTF 2023

After some easy trivia challenges in the DRAGOS 2023 CTF, the first 200 points challenge, called “Global Session planning” was a stegano challenge. I provide below just a focus on a flag hidden in the JPG file only in one of the first easy challenges.

 


Attached to the challenge was provided a “manekineko.jpg” accompanied with below text:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

After trying most of the “usual easy tools” to retrieve a flag in a steganography challenge :

  • strings : no strings of interest
  • exiftool : no flag
  • binwalk : no file included
  • metadata : no metadata
  • change of colors, gradient, error level analysis….etc : nothing
  • …etc)
  • jsteg was also unsucessful
#https://github.com/lukechampine/jsteg/
─$ jsteg reveal manekineko.jpg
could not decode jpeg:unsupported JPEG feature: progressive decoding

I finally used outguess-extract and got an interesting clue as below:

outguess-extract manekineko.jpg test.jpg
Reading manekineko.jpg....
Corrupt JPEG data: 8332 extraneous bytes before marker 0xc4
Having an “extraneous bytes before marker” was a sign that the probable technique used was a change of size of the picture !
Based on some links from cyberhacktics  and  hackmd.io  I got the tip to edit the JPG Height starting at the FFC2 marker.
On kali I used the practical wxhexEditor and updated the first byte for the height  (04  to 06)

 

 

 

 

We play with the initial height  (just after the “Data precision ” byte) :

 

It was then easy to to visualize the flag as flag{not_everything_is_as_it_seems}.

It is interesting to note that the initial marker pointed 0xC4 is DHT 0xFF, 0xC4  variable size Define Huffman Table(s) Specifies one or more Huffman tables.

aside

Home

Articles on various topics like security, cyber security, scuba-diving, machine-learning,…etc  !