Comment by formerly_proven

13 days ago

As per the PoC, yes — this is the usual Java Deserialization RCE where it’ll instantiate arbitrary classes. Java serialization really is a gift that keeps on giving.

I love how these always instantly escalate into trivial code execution / reverse shell. Remember kids, C is the enemy!

The "fix" in question also screams "delete this crap immediately": https://github.com/wgtmac/parquet-mr/commit/d185f867c1eb968a...

  • The fix still loads the class before checking if it’s okay.

    That’s a smaller attack window but it’s still not zero.

  • This is a bug in Java. Java is considered "memory safe" because of its GC and its VM. This is not a memory safety bug.

    • It's true. No memory is being used in contravention of the language semantics. Absolutely memory safe.