Technical Advisory – Multiple HTML Injection Vulnerabilities in KaiOS Pre-installed Mobile Applications

Multiple HTML injection vulnerabilities were found in several KaiOS mobile applications that are pre-installed on KaiOS mobile devices.

The following vulnerabilities affected multiple KaiOS mobile devices:

Technical Advisories:

KaiOS Email Application HTML Injection (CVE-2019-14756)

Vendor: KaiOS Technologies Inc.
Vendor URL: https://www.kaiostech.com/
Versions affected: KaiOS 1.0, KaiOS 2.5, KaiOS 2.5.1
Systems Affected: KaiOS-based mobile devices
Author: Neil Bergman 
CVE Identifier: CVE-2019-14756
Risk: High

Summary

KaiOS is a mobile operating system based on Firefox OS. The operating system comes with a number of pre-installed “certified” applications including the Email application, which allows a user to view their emails on the mobile device. Firefox OS mobile applications are built using JavaScript and HTML.

The Email application is vulnerable to HTML and JavaScript injection attacks.

Location

  • /system/b2g/webapps/email.gaiamobile.org

Impact

An attacker can send a specially crafted email to the victim which will inject in HTML into the email application’s UI as soon as the email is opened. At a bare minimum this allows an attacker to take control over the Email application’s UI and display a malicious prompt to the user asking them to re-enter their email credentials.

We have also demonstrated that it is possible to bypass the default CSP used by certified applications, which allows a remote attacker to inject in JavaScript that will execute in the context of the Email application, which has access to sensitive Web APIs, such as the storage, settings, and contacts Web APIs, which would allow a remote attacker to steal files stored on the SD card, such as the user’s photos, videos, or audio, and alter device settings.

Details

The Email application is vulnerable to HTML injection when rendering an email with an attachment filename that contains HTML content.

Privileged and certified mobile applications use a default Content Security Policy to prevent JavaScript injection, but we are able to bypass the CSP by injecting in an iframe using the srcdoc attribute, which is a publicly documented technique.

The following video demonstrates that remote exploitation resulting in remote file disclosure is possible.

Recommendation

Avoid using HTML/JavaScript injection sinks such as the innerHTML property and use the innerText property instead or manually perform HTML output encoding or input validation on user inputs to mobile applications.

KaiOS Contacts Application HTML Injection (CVE-2019-14757)

Vendor: KaiOS Technologies Inc.
Vendor URL: https://www.kaiostech.com/
Versions affected: KaiOS 2.5, KaiOS 2.5.1
Systems Affected: KaiOS-based mobile devices
Author: Neil Bergman 
CVE Identifier: CVE-2019-14757
Risk: Medium

Summary

KaiOS is a mobile operating system based on Firefox OS. The operating system comes with a number of pre-installed “certified” applications including the Contacts application, which allows a user to view and edit a list of contacts on the mobile device. Firefox OS mobile applications are built using JavaScript and HTML.

The Contacts application is vulnerable to HTML and JavaScript injection attacks.

Location

  • /system/b2g/webapps/contact.gaiamobile.org

Impact

An attacker can send a vCard file to the victim which will inject HTML into the Contacts application assuming the victim chooses to import the file. At a bare minimum this allows an attacker to take control over the Contacts application’s UI and display a malicious prompt to the user asking them to re-enter credentials such as their KaiOS credentials to continue using the application.

It is also possible to bypass the default CSP used by certified applications, which allows a remote attacker to inject in JavaScript that will execute in the context of the Contacts application, which has access to sensitive Web APIs, such as the storage, settings, and contacts Web APIs, which would allow a remote attacker to steal files stored on the SD card, such as the user’s photos, videos, or audio, and alter device settings.

Details

The Contacts application is vulnerable to HTML injection when rendering a contact that contains HTML in its first or last name.

The vulnerability could be exploited remotely if an attacker creates a vCard file using the a first or last name that includes HTML content. The attacker then sends the vCard file as an email attachment to an email account that is setup on the mobile device. When the user selects the attachment from within the Email mobile application, then the Contacts application will open. If the user agrees to save the contact and then reopen the Contacts application then HTML injection will occur.

Privileged and certified mobile applications use a default Content Security Policy to prevent JavaScript injection, but we have noted that we are able to bypass the CSP by injecting in an iframe using the srcdoc attribute, which is a publicly documented technique.

Recommendation

Avoid using HTML/JavaScript injection sinks such as the innerHTML property and use the innerText property instead or manually perform HTML output encoding or input validation on user inputs to mobile applications.

KaiOS File Manager Application HTML Injection (CVE-2019-14758)

Vendor: KaiOS Technologies Inc.
Vendor URL: https://www.kaiostech.com/
Versions affected: KaiOS 2.5, KaiOS 2.5.1
Systems Affected: KaiOS-based mobile devices
Author: Neil Bergman 
CVE Identifier: CVE-2019-14758
Risk: Medium

Summary

KaiOS is a mobile operating system based on Firefox OS. The operating system comes with a number of pre-installed “certified” applications including the File Manager application, which allows the user to view and delete files on the device’s internal storage or external storage. Firefox OS mobile applications are built using JavaScript and HTML.

The File Manager application is vulnerable to HTML and JavaScript injection attacks.

Location

  • /system/b2g/webapps/filemanager.gaiamobile.org

Impact

An attacker can send a file via email to the victim which will inject in HTML into the File Manager application assuming the victim chooses to download the email attachment and view the downloads directory via the File Manager. Note that the KaiOS browser sanitizes filenames of files downloaded from the Internet, but other third-party KaiOS mobile applications could also download files over the Internet with malicious filenames that would trigger this vulnerability. Alternatively, a file, with a malicious filename, could be transferred via USB to a mobile device if attached to a hostile computer. At a bare minimum this allows an attacker to take control over the File Manager application’s UI and display a malicious prompt to the user asking them to re-enter credentials such as their KaiOS credentials to continue using the application.

We have also demonstrated that it is possible to bypass the default CSP used by certified applications, which allows a remote attacker to inject in JavaScript that will execute in the context of the File Manager application, which has access to sensitive Web APIs, such as the storage Web APIs, which would allow a remote attacker to steal files stored on the SD card, such as the user’s photos, videos, or audio. On mobile devices where the File Manager has been granted access to an undocumented engineering mode Web API it is possible to execute arbitrary OS commands as the root user by exploiting this vulnerability.

Details

The File Manager application is vulnerable to HTML injection when rendering a filename that contains HTML.

The vulnerability can be exploited locally by connecting the mobile device to a computer using USB and transferring the malicious file to the mobile device’s internal storage using MTP. Opening the File Manager application and viewing the malicious filename triggers HTML injection into the mobile application.

The vulnerability can be exploited remotely by sending the file as an email attachment to an email account that is setup on the mobile device. If the user downloads the file attachment and then accesses the downloads directory via the File Manager application.

Privileged and certified mobile applications use a default Content Security Policy to prevent JavaScript injection, but we have noted that we are able to bypass the CSP by injecting in an iframe using the srcdoc attribute, which is a publicly documented technique.

Recommendation

Avoid using HTML/JavaScript injection sinks such as the innerHTML property and use the innerText property instead or manually perform HTML output encoding or input validation on user inputs to mobile applications.

KaiOS Recorder Application HTML Injection (CVE-2019-14760)

Vendor: KaiOS Technologies Inc.
Vendor URL: https://www.kaiostech.com/
Versions affected: KaiOS 2.5
Systems Affected: KaiOS-based mobile devices
Author: Neil Bergman 
CVE Identifier: CVE-2019-14760
Risk: Low

Summary

KaiOS is a mobile operating system based on Firefox OS. The operating system comes with a number of pre-installed “certified” applications including the Recorder application, which allows the user to record and listen to audio. Firefox OS mobile applications are built using JavaScript and HTML.

The Recorder application is vulnerable to HTML and JavaScript injection attacks.

Location

  • /system/b2g/webapps/soundrecorder.gaiamobile.org

Impact

A local attacker can inject arbitrary HTML into the Recorder application. At a bare minimum this allows an attacker to take control over the Recorder application’s UI and display a malicious prompt to the user asking them to re-enter credentials such as their KaiOS credentials to continue using the application.

It is also possible to bypass the default CSP used by certified applications, which allows a local attacker to inject in JavaScript that will execute in the context of the Recorder application, which has access to sensitive Web APIs, such as the storage and settings Web APIs, which would allow a local attacker to manipulate files stored on the SD card, such as the user’s photos, videos, or audio, and alter device settings.

Details

The Recorder application is vulnerable to HTML injection when rendering the name of a recording.

The vulnerability can be exploited locally by opening the Recorder application and creating a new audio recording with a name that contains HTML.

Privileged and certified mobile applications use a default Content Security Policy to prevent JavaScript injection, but we have noted that we are able to bypass the CSP by injecting in an iframe using the srcdoc attribute, which is a publicly documented technique.

Recommendation

Avoid using HTML/JavaScript injection sinks such as the innerHTML property and use the innerText property instead or manually perform HTML output encoding or input validation on user inputs to mobile applications.

KaiOS Note Application HTML Injection (CVE-2019-14761)

Vendor: KaiOS Technologies Inc.
Vendor URL: https://www.kaiostech.com/
Versions affected: KaiOS 2.5
Systems Affected: KaiOS-based mobile devices
Author: Neil Bergman 
CVE Identifier: CVE-2019-14761
Risk: Low

Summary

KaiOS is a mobile operating system based on Firefox OS. The operating system comes with a number of pre-installed “certified” applications including the Note application, which allows the user to record simple text notes. Firefox OS mobile applications are built using JavaScript and HTML.

The Note application is vulnerable to HTML and JavaScript injection attacks.

Location

  • /system/b2g/webapps/notes.gaiamobile.org

Impact

A local attacker can inject arbitrary HTML into the Note application. At a bare minimum this allows an attacker to take control over the Note application’s UI and display a malicious prompt to the user asking them to re-enter credentials such as their KaiOS credentials to continue using the application.

We have also demonstrated that it is possible to bypass the default CSP used by certified applications, which allows a local attacker to inject in JavaScript that will execute in the context of the Note application, which has access to sensitive Web APIs, such as the storage Web APIs, which would allow a local attacker to manipulate files stored on the SD card, such as the user’s photos, videos, or audio.

Details

The Note application is vulnerable to HTML injection when rendering the contents of the note on the main application screen.

The vulnerability can be exploited locally by opening the Note application and creating a new note with contents that contains HTML.

Privileged and certified mobile applications use a default Content Security Policy to prevent JavaScript injection, but we have noted that we are able to bypass the CSP by injecting in an iframe using the srcdoc attribute, which is a publicly documented technique.

Recommendation

Avoid using HTML/JavaScript injection sinks such as the innerHTML property and use the innerText property instead or manually perform HTML output encoding or input validation on user inputs to mobile applications.

KaiOS FM Radio HTML Injection (CVE-2019-14759)

Vendor: KaiOS Technologies Inc.
Vendor URL: https://www.kaiostech.com/
Versions affected: KaiOS 1.0, KaiOS 2.5, KaiOS 2.5.1
Systems Affected: KaiOS-based mobile devices
Author: Neil Bergman 
CVE Identifier: CVE-2019-14759
Risk: Low

Summary

KaiOS is a mobile operating system based on Firefox OS. The operating system comes with a number of pre-installed “certified” applications including the FM Radio application, which allows the user to listen to the radio. Firefox OS mobile applications are built using JavaScript and HTML.

The FM Radio application is vulnerable to HTML and JavaScript injection attacks.

Location

  • /system/b2g/webapps/fm.gaiamobile.org

Impact

A local attacker can inject arbitrary HTML into the FM Radio application. At a bare minimum this allows an attacker to take control over the FM Radio application’s UI and display a malicious prompt to the user asking them to re-enter credentials such as their KaiOS credentials to continue using the application.

We have also demonstrated that it is possible to bypass the default CSP used by certified applications, which allows a local attacker to inject in JavaScript that will execute in the context of the FM Radio application, but the FM Radio has limited application permissions, but the injected HTML or JavaScript code could prevent a user from using the FM Radio application until a factory reset.

Details

The FM Radio application is vulnerable to HTML injection when rendering the name of a favorite radio station on the main application screen.

The vulnerability can be exploited locally by opening the FM Radio application, selecting a radio station, marking it as a favorite, and changing the station name to include HTML.

Privileged and certified mobile applications use a default Content Security Policy to prevent JavaScript injection, but we have noted that we are able to bypass the CSP by injecting in an iframe using the srcdoc attribute, which is a publicly documented technique.

Recommendation

Avoid using HTML/JavaScript injection sinks such as the innerHTML property and use the innerText property instead or manually perform HTML output encoding or input validation on user inputs to mobile applications.

Vendor Communication Timeline

  • 7/25/19: NCC Group emailed security@kaiostech.com asking for PGP key used for secure communication.
  • 7/25/19: NCC Group disclosed issues to KaiOS Technologies.
  • 8/13/19: NCC Group asked for current remediation status.
  • 8/14/19: Received notice from KaiOS Technologies that fixes for all the defects were implemented, and they are working with OEMs to push them to production through system updates. Additional time was given to allow OEMs to patch, but it is up to each OEM to decide whether or not to accept the KaiOS patches.

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