External risk intelligence

Huawei EMUI HarmonyOS Installd Module Unauthorized File Access Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2023-39402

The vulnerability exists in the installd module of Huawei EMUI and HarmonyOS, which are mobile operating system components. These modules handle local package installation and application management tasks. They are not designed to be public-facing network services and operate within the local environment of a mobile device, making public internet exposure of this specific attack surface very unlikely.

Path Traversal

Huawei Emui

11.0.112.0.012.0.113.0.02.0.02.0.12.1.03.0.03.1.0

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the installd module of Huawei EMUI and HarmonyOS could allow unauthorized reading and writing of sandbox files. This means that sensitive application data might be compromised without proper authorization. The primary concern is to confirm if these affected systems are in use and if the specific functionality is exposed to risk.

Local software installer has a security flaw.
It could allow unauthorized access to app data.
Confirm relevance and exposure of affected systems.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by leveraging the installd module, which handles package installation, to bypass parameter verification. This could allow unauthorized reading and writing of sandbox files, potentially leading to unauthorized data access and modification.

No authentication or privileges needed.
Triggered by malformed installation parameters.
Unauthorized file read/write access.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow unauthorized reading and writing of sandbox files when the installd module's parameter verification fails. This means that sensitive application data or system files within restricted areas of the operating system may be accessed and modified.

Sandbox files could be read or written.
Exploitation may occur through module interaction.
Unauthorized data access and modification.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability affects Huawei's EMUI and HarmonyOS. Responsibility for addressing this likely falls to platform or device operations teams responsible for managing the operating system, in coordination with vendor management if direct vendor support is required. The immediate first step is to inventory all instances of the affected operating systems, determine their reachability and criticality, and then identify the specific asset owners to plan a coordinated response.

Own by platform and device operations teams.
Verify system reachability and criticality.
Plan remediation with asset owners.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the installd module in Huawei EMUI and HarmonyOS?

The installd module is a background system component responsible for managing the installation, updates, and removal of applications on Huawei's mobile operating systems. It acts as an internal service that handles the technical details of how software is placed into secure storage areas, known as sandboxes, to ensure each application remains isolated from others.

What does CVE-2023-39402 mean for system security?

This vulnerability is classified under Improper Limitation of a Pathname to a Restricted Directory (CWE-22) and Improper Authorization (CWE-285). It signifies a breakdown in the system's ability to verify instructions sent to the installd module. Because the system fails to validate these parameters, an attacker could bypass standard security boundaries to read or modify files that should be restricted to specific applications.

How is the installd module flaw triggered?

The vulnerability is triggered by sending malformed or malicious installation parameters to the installd module. It does not require the attacker to have existing privileges or authentication on the device. However, simply having the operating system installed is not enough; the bug specifically requires active interaction with the module's parameter handling functions to bypass security checks.

Do I need to worry about internet-facing exposure?

According to Halo Surface Signal, this is very unlikely. The affected module is a local component designed for internal system management on mobile devices, not a public-facing network service. While the CVSS vector lists a network attack vector, the component's role within the local device environment makes it difficult to reach directly from the public internet.

What is the first step to address this CVE?

Your priority should be to perform an inventory of all devices running the affected versions of EMUI and HarmonyOS. Once you identify which assets are in use, work with your device management teams to assess the criticality of these systems and determine if they are configured to allow any external interaction that could potentially reach the local installd module.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.