From 0eaedc6a619799452fd5003180baacf66c1345c9 Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Mon, 3 Oct 2022 21:27:23 +0000 Subject: [PATCH] vuln-fix: Zip Slip Vulnerability This fixes a Zip-Slip vulnerability. This change does one of two things. This change either 1. Inserts a guard to protect against Zip Slip. OR 2. Replaces `dir.getCanonicalPath().startsWith(parent.getCanonicalPath())`, which is vulnerable to partial path traversal attacks, with the more secure `dir.getCanonicalFile().toPath().startsWith(parent.getCanonicalFile().toPath())`. For number 2, consider `"/usr/outnot".startsWith("/usr/out")`. The check is bypassed although `/outnot` is not under the `/out` directory. It's important to understand that the terminating slash may be removed when using various `String` representations of the `File` object. For example, on Linux, `println(new File("/var"))` will print `/var`, but `println(new File("/var", "/")` will print `/var/`; however, `println(new File("/var", "/").getCanonicalPath())` will print `/var`. Weakness: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') Severity: High CVSSS: 7.4 Detection: CodeQL (https://codeql.github.com/codeql-query-help/java/java-zipslip/) & OpenRewrite (https://public.moderne.io/recipes/org.openrewrite.java.security.ZipSlip) Reported-by: Jonathan Leitschuh Signed-off-by: Jonathan Leitschuh Bug-tracker: https://github.com/JLLeitschuh/security-research/issues/16 Co-authored-by: Moderne --- .../org/projectodd/wunderboss/ApplicationRunner.java | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/core/src/main/java/org/projectodd/wunderboss/ApplicationRunner.java b/core/src/main/java/org/projectodd/wunderboss/ApplicationRunner.java index 21f4bbe..bb4a465 100644 --- a/core/src/main/java/org/projectodd/wunderboss/ApplicationRunner.java +++ b/core/src/main/java/org/projectodd/wunderboss/ApplicationRunner.java @@ -18,10 +18,7 @@ import org.slf4j.Logger; -import java.io.File; -import java.io.FileInputStream; -import java.io.FileOutputStream; -import java.io.InputStream; +import java.io.*; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; @@ -125,7 +122,10 @@ public void run() { if (!match) { continue; } - File file = new File(extractRoot + "/" + name); + File file = new File(extractRoot, name); + if (!file.toPath().normalize().startsWith(extractRoot)) { + throw new IOException("Bad zip entry"); + } if (zipEntry.isDirectory()) { file.mkdirs(); } else {