Impact

Given specially crafted zip or JAR file, IO.unzip allows writing of arbitrary file. The follow is an example of a malicious entry:

+2018-04-15 22:04:42 ..... 20 20 ../../../../../../root/.ssh/authorized_keys

This would have a potential to overwrite /root/.ssh/authorized_keys. Within sbt's main code, IO.unzip is used in pullRemoteCache task and Resolvers.remote; however many projects use IO.unzip(...) directly to implement custom tasks - https://github.com/search?q=IO.unzip+language%3AScala&type=code&l=Scala&p=1

Patches

The problem has been patched in sbt/io#360
sbt 1.9.7 is available with the fix.

Workarounds

A workaround might be use some other library to unzip.

References

• https://github.com/snyk/zip-slip-vulnerability
• https://security.snyk.io/vuln/SNYK-JAVA-ORGCODEHAUSPLEXUS-31680
• sbt/io#358