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improve stage 2 detection #50

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improve stage 2 detection #50

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93 changes: 58 additions & 35 deletions src/main/java/me/cortex/jarscanner/Detector.java
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Original file line number Diff line number Diff line change
Expand Up @@ -303,61 +303,84 @@ public static boolean scanClass(byte[] clazz) {
}

/**
* Checks for signs of stage 2 infection and returns a list of files that are flagged as suspicious.
* Checks for signs of stage 2 infection and returns a list of files that are
* flagged as suspicious.
* Based on:
* https://github.com/fractureiser-investigation/fractureiser#am-i-infected
* https://prismlauncher.org/news/cf-compromised-alert/#automated-script
*/
public static List<String> checkForStage2() {
public static List<String> checkForStage2(Function<String, String> output) {
// Create list to store suspicious files found
List<String> suspiciousFilesFound = new ArrayList<>();

// windows checks
Path windowsStartupDirectory = (Objects.isNull(System.getenv("APPDATA"))
? Paths.get(System.getProperty("user.home"), "AppData", "Roaming")
: Paths.get(System.getenv("APPDATA"), new String[0]))
.resolve(Paths.get("Microsoft", "Windows", "Start Menu", "Programs", "Startup"));
boolean windows = Files.isDirectory(windowsStartupDirectory, new LinkOption[0])
&& Files.isWritable(windowsStartupDirectory);

String[] maliciousFiles = {
".ref",
"client.jar",
"lib.dll",
"libWebGL64.jar",
"run.bat"
};
Path userHome = Paths.get(System.getProperty("user.home"));

String os = System.getProperty("os.name").toLowerCase();
boolean windows = os.contains("windows");

File dataFolder;

if (windows) {
// only checking for the folder because the file can be renamed
File edgeFolder = new File(System.getenv("APPDATA") + "\\Microsoft Edge");
if (edgeFolder.exists()) {
suspiciousFilesFound.add(edgeFolder.getAbsolutePath());
}
Path windowsAppData = Paths.get(userHome.toString(), "AppData");
dataFolder = Paths.get(windowsAppData.toString(), "Local", "Microsoft Edge").toFile();

File startFolder = new File("Microsoft\\Windows\\Start Menu\\Programs\\Startup");
// get all files in the startup folder, and check if they match the malicious
Path windowsStartupDirectory = Paths.get(windowsAppData.toString(), "Roaming", "Microsoft", "Windows",
"Start Menu", "Programs", "Startup");

File startFolder = windowsStartupDirectory.toFile();
// check for run.bat (or a shortcut to it)
if (startFolder.exists() && startFolder.isDirectory()) {
File[] startFiles = startFolder.listFiles();

for (int i = 0; i < startFiles.length; i++) {

for (int j = 0; j < maliciousFiles.length; j++) {
if (startFiles[i].getName().equals(maliciousFiles[j])) {
suspiciousFilesFound.add(startFiles[i].getAbsolutePath());
}
for (File startFile : startFiles) {
if (startFile.getName().contains("run.bat")) {
suspiciousFilesFound.add(startFile.getAbsolutePath());
}
}
}

// check for known registry key used to start run.bat
String err = "Couldn't run reg.exe! Please check HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\t manually";
String regKey = "HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\t";
try {
Process regQuery = Runtime.getRuntime()
.exec("reg.exe query " + regKey);
regQuery.waitFor();

int returnCode = regQuery.exitValue();
if (returnCode == 0) {
suspiciousFilesFound.add(regKey);
}
} catch (IOException e) {
output.apply(err);
} catch (InterruptedException e) {
output.apply(err);
}

}

// linux checks
if (System.getProperty("os.name").toLowerCase().contains("linux")) {
File file = new File("~/.config/.data/lib.jar");
if (file.exists()) {
suspiciousFilesFound.add(file.getAbsolutePath());
// we are going to assume linux here, as it's the only other platform affected
else {
Path linuxConfig = Paths.get(userHome.toString(), ".config");
dataFolder = Paths.get(linuxConfig.toString(), ".data").toFile();

// check for malicious systemd services
String maliciousService = "systemd-utility.service";
File[] systemdFolders = new File[]{ Paths.get(linuxConfig.toString(), "systemd", "user").toFile(), Paths.get("/etc", "systemd", "system").toFile() };

for (File folder : systemdFolders) {
File service = Paths.get(folder.toString(), maliciousService).toFile();
if (service.exists()) {
suspiciousFilesFound.add(service.getAbsolutePath());
}
}
}

// only checking for the folder because the file can be renamed
if (dataFolder.exists() && dataFolder.isDirectory()) {
suspiciousFilesFound.add(dataFolder.getAbsolutePath());
}

// Return list of suspicious files found
return suspiciousFilesFound;
}
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2 changes: 1 addition & 1 deletion src/main/java/me/cortex/jarscanner/Main.java
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Original file line number Diff line number Diff line change
Expand Up @@ -246,7 +246,7 @@ public FileVisitResult postVisitDirectory(Path dir, IOException exc) {
// Run stage 2 scan
long stage2StartTime = System.currentTimeMillis();
logOutput.apply(Constants.ANSI_GREEN + "Running Stage 2 Scan..." + Constants.ANSI_RESET);
List<String> stage2InfectionsList = Detector.checkForStage2();
List<String> stage2InfectionsList = Detector.checkForStage2(logOutput);
long stage2EndTime = System.currentTimeMillis();
long stage2Time = stage2EndTime - stage2StartTime;
logOutput.apply(Constants.ANSI_GREEN + "Stage 2 Scan Complete - " + Constants.ANSI_RESET + "Took " + stage2Time + "ms.");
Expand Down