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Local Information Disclosure Vulnerability in io.netty:netty-codec-http

Moderate severity GitHub Reviewed Published May 6, 2022 in netty/netty • Updated Jan 27, 2023

Package

maven io.netty:netty-codec-http (Maven)

Affected versions

<= 4.1.76.Final

Patched versions

4.1.77.Final

Description

Description

GHSA-5mcr-gq6c-3hq2 (CVE-2021-21290) contains an insufficient fix for the vulnerability identified.

Impact

When netty's multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled.

This only impacts applications running on Java version 6 and lower. Additionally, this vulnerability impacts code running on Unix-like systems, and very old versions of Mac OSX and Windows as they all share the system temporary directory between all users.

Vulnerability Details

To fix the vulnerability the code was changed to the following:

    @SuppressJava6Requirement(reason = "Guarded by version check")
    public static File createTempFile(String prefix, String suffix, File directory) throws IOException {
        if (javaVersion() >= 7) {
            if (directory == null) {
                return Files.createTempFile(prefix, suffix).toFile();
            }
            return Files.createTempFile(directory.toPath(), prefix, suffix).toFile();
        }
        if (directory == null) {
            return File.createTempFile(prefix, suffix);
        }
        File file = File.createTempFile(prefix, suffix, directory);
        // Try to adjust the perms, if this fails there is not much else we can do...
        file.setReadable(false, false);
        file.setReadable(true, true);
        return file;
    }

Unfortunately, this logic path was left vulnerable:

        if (directory == null) {
            return File.createTempFile(prefix, suffix);
        }

This file is still readable by all local users.

Patches

Update to 4.1.77.Final

Workarounds

Specify your own java.io.tmpdir when you start the JVM or use DefaultHttpDataFactory.setBaseDir(...) to set the directory to something that is only readable by the current user or update to Java 7 or above.

References

For more information

If you have any questions or comments about this advisory:

Open an issue in netty

References

@normanmaurer normanmaurer published to netty/netty May 6, 2022
Published by the National Vulnerability Database May 6, 2022
Published to the GitHub Advisory Database May 10, 2022
Reviewed May 10, 2022
Last updated Jan 27, 2023

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS score

0.044%
(11th percentile)

CVE ID

CVE-2022-24823

GHSA ID

GHSA-269q-hmxg-m83q

Source code

Credits

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