From d07b0f8aa32532312cec1e962ed4aeccc494b281 Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Fri, 9 Sep 2022 03:02:58 +0000 Subject: [PATCH] vuln-fix: Partial Path Traversal Vulnerability This fixes a partial path traversal vulnerability. 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())`. To demonstrate this vulnerability, 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: Medium CVSSS: 6.1 Detection: CodeQL & OpenRewrite (https://public.moderne.io/recipes/org.openrewrite.java.security.PartialPathTraversalVulnerability) Reported-by: Jonathan Leitschuh Signed-off-by: Jonathan Leitschuh Bug-tracker: https://github.com/JLLeitschuh/security-research/issues/13 Co-authored-by: Moderne --- .../com/amazonaws/serverless/proxy/internal/SecurityUtils.java | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/SecurityUtils.java b/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/SecurityUtils.java index d553d17a7..0023104a7 100644 --- a/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/SecurityUtils.java +++ b/aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/SecurityUtils.java @@ -201,7 +201,7 @@ public static String getValidFilePath(final String inputPath, boolean isWrite) { try { String canonicalPath = f.getCanonicalPath(); - if (isWrite && canonicalPath.startsWith("/var/task")) { + if (isWrite && f.getCanonicalFile().toPath().startsWith("/var/task")) { throw new IllegalArgumentException("Trying to write to /var/task folder"); }