java.lang.NullPointerException in net.lingala.zip4j.io.inputstream.ZipInputStream.getEncryptionHeaderSize::ZipInputStream.java:336 zip4j 2.9.0

[ZanderHuang]

This vulnerability is of java.lang.NullPointerException, and can be triggered in latest version zip4j (2.9.0).
It is caused by not checking the pointer before dereference it and also failing to catch the runtime java exception (it should be wrapped as one kind of JSONException) and can be used for attackers to launch DoS (Denial of Service) attack for any java program that uses this library (since the user of zip4j doesn't know they need to catch this kind of exception) (CWE-476: NULL Pointer Dereference, CWE-248: Uncaught exception).
Likely, the root cause of this crash is in net.lingala.zip4j.io.inputstream.ZipInputStream.getEncryptionHeaderSize::ZipInputStream.java:336.

zip4j/src/main/java/net/lingala/zip4j/io/inputstream/ZipInputStream.java

Line 336 in ce1cff6

+ localFileHeader.getAesExtraDataRecord().getAesKeyStrength().getSaltLength();

The variable "localFileHeader" has a NULL value and it results in NullPointerException.

See more detail from the following crash stack.

Crash stack:

The crash thread's stack is as follows:

net.lingala.zip4j.io.inputstream.ZipInputStream.getEncryptionHeaderSize::ZipInputStream.java:336
net.lingala.zip4j.io.inputstream.ZipInputStream.getCompressedSize::ZipInputStream.java:326
net.lingala.zip4j.io.inputstream.ZipInputStream.initializeEntryInputStream::ZipInputStream.java:222
net.lingala.zip4j.io.inputstream.ZipInputStream.getNextEntry::ZipInputStream.java:113
net.lingala.zip4j.io.inputstream.ZipInputStream.getNextEntry::ZipInputStream.java:83
com.test.Entry.main::Entry.java:37

Steps to reproduce:

1. Build the following java code with the corresponding zip4j library (version 2.9.0).

## Download zip4j_env_reproduce.tar.gz from https://drive.google.com/file/d/1MekCBIghKxIW4j-TLjZkm8ovvLb_grm5/view?usp=sharing
tar -xf zip4j_env_reproduce.tar.gz
cd zip4j_env_reproduce
bash build.sh

2. Run the built program to see the crash by feeding one of the poc file contained in the pocs.tar.gz, e.g. :
   (poc file can be downloaded from https://drive.google.com/file/d/1wdvxU5bX_Fw9DtupwpDsTJU2JMKAnUuy/view?usp=sharing)

java -jar target/Entry-1.0-SNAPSHOT-jar-with-dependencies.jar pocs/crash-a49f954b47e05cc5265db441a64e5d2d55cb33b8

Any further discussion for this vulnerability including fix is welcomed!

[srikanth-lingala]

Fixed in v2.10.0 released today