From 2ce3b4a1f3bd2cd120b56f3d79fc3bcdba8710e4 Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Fri, 4 Nov 2022 15:08:58 +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 --- ache/src/main/java/achecrawler/crawler/CrawlersManager.java | 3 +++ 1 file changed, 3 insertions(+) diff --git a/ache/src/main/java/achecrawler/crawler/CrawlersManager.java b/ache/src/main/java/achecrawler/crawler/CrawlersManager.java index 591231974..4b886df72 100644 --- a/ache/src/main/java/achecrawler/crawler/CrawlersManager.java +++ b/ache/src/main/java/achecrawler/crawler/CrawlersManager.java @@ -199,6 +199,9 @@ private void unzipFile(Path file, Path outputDir) throws IOException { continue; } File entryDestination = new File(outputDir.toFile(), entry.getName()); + if (!entryDestination.toPath().normalize().startsWith(outputDir.toFile().toPath().normalize())) { + throw new IOException("Bad zip entry"); + } if (entry.isDirectory()) { entryDestination.mkdirs(); } else {