ysoserial VS Logback

So I've finished the unified box in stage 2 of the starting point and have tons of questions about the box. In the box they use veracode-research/rogue-jndi to exploit the log4j vulnerability. But when I test it with deserialize payload generated by frohoff/ysoserial it's not running. I've try to look at the java log in the challenge container but can't find anything that java complain or error out. Is it because the ysoserial payload too complex that it running but fail at some point and don't throw error or maybe the author just hard code so that only the payload from rogue-jndi work? can it's because of the java version/framework/library/weirdness? Do I need to test both kind of payload if I want to exploit log4j in the future or just stick with pimps/JNDI-Expoit-Kit or cckuailong/JNDI-Injection_Exploit-Plus (my senior recommendation when exploiting log4j).

GitHub - Ysoserial

A gadget lets you run load a different class upon serialization. This will fail later when we downcast but during the read process we can load a different class where we can do arbitrary code execution. HashMap is a class that overrides the readObject and can be used as part of an exploit chain. ysoserial helps us create a chain of serialization to produce an exploit based on known serialization weaknesses. You can run this project and generate payload ser files that you can pass to exploit potential vulnerabilities.

gadget chain attack: is a type of exploit where an attacker uses a series of "gadgets" — small pieces of code that perform a specific function — to execute a larger, more complex attack. By chaining together these gadgets, an attacker can gain control of a target system or perform other malicious actions. You can use ysoserial to create a serialize payload java -jar path/to/ysoserial.jar CommonsCollections4 'whoami'

> A similar issue has occurred with Java (and other languages, see https://frohoff.github.io/appseccali-marshalling-pickles/). Java provided a suberbly user-friendly way of serializing any object to disk and recovering it back in its original form. The only unfortunate problem was that there was no way to say which object you are expecting! This allows attackers to send you objects that, upon deserialization in your program, become nasties that wreak havoc and steal data.

Not correct. You can certainly inspect before instantiation:

https://docs.oracle.com/javase/7/docs/platform/serialization...

Mmh, I don't think so. Beside logging most other libraries will already sanitize user input since it is a more commonly known attack vector for those kind of libraries. I would compare the vulnerability to https://github.com/frohoff/ysoserial.

Exactly. eg. https://github.com/frohoff/ysoserial#usage

Note the classes aren't at fault or doing anything wrong (even though you could imagine other mitigations they could use), they are just conveniently there to use if you have a vulnerability that lets you de-serialize untrusted data.

This has been known for a zillion years and has caused a zillion CBEs, so at this point there are off-the-shelf tools like ysoserial that take your payload and wrap it into an object that kabooms when deserialized, with like 20 different choices of methods depending on what dangerous objects are available on the target's classpath for deserialization.

Java -> Logback, Log4j2, JDK (Java Util Logging), Slf4j, e.t.c.

This is a GitHub link to my demo app. It’s simple Spring Boot web app used to debugging various stuff. There are many ways to configure JSON logging in Spring Boot. I decided to use Logback because it is easy to configure and one of the most widely used logging library in the Java Community. To enable JSON logging we need to add below dependencies.

Logback(https://logback.qos.ch/) is another non-commercial Java logging framework. It labels itself as a successor to the previously discussed Log4j framework.

> Then apache decides to put new people on log4j, do a backward incompatible v2 design that nevertheless is worse than slf4j. Why?

slf4j itself isn't a logging framework. It's a facade to logging frameworks.

Simple Logging Facade for Java ( https://www.slf4j.org )

It needs a logging framework behind it - log4j, log4j2, logback, commons, JUL.

The question is "why do log4j2?"

Logback went from the log4j1.x path ( https://logback.qos.ch )

Log4j2 has a lot of features that weren't present when the project started ( https://en.wikipedia.org/wiki/Log4j#Apache_Log4j_2 ).

There is a licensing difference between Logback (LGPL) and Log4jx (Apache Commons).

Also, I'd like you to pay attention to the log consumer. You see, when the E2E scenario fails, it's not always obvious why. Sometimes to understand the source of the problem you have to dig into containers' logs. Thankfully the log consumer allows us to forward a container's logs to any SLF4J logger instance. In this project, containers' logs are forwarded to regular text files (you can find the Logback configuration in the repository). Though it's much better to transfer logs to external logging facility (e.g. Kibana).

This shows that the MariaDB JDBC driver uses Logback as a logging framework. Although Logback is not affected by Log4Shell, it has a related vulnerability (of much lesser severity, no need to panic) fixed in version 1.2.8 and 1.3.0-alpha11. I checked the version used by the connector and found that it used 1.3.0-alpha10. Even though Logback is included as a test dependency in the MariaDB driver, I sent a pull request on GitHub to update it. I encourage you to do the same in any open-source project you find and that includes a vulnerable dependency.

Dependencing on the project, changing the logger might range from easy peasy to a multi-week task. I'm ready to bet that in many (most?) cases, it'd actually be quite easy, so let's explore how to do it, using Logback as the target (there aren't that many alternatives actually).