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Three Security Vulnerabilities in the Audio Decoders Affects Millions of Android Devices

Three security vulnerabilities have been reported in the audio decoders of MediaTek and Qualcomm chips. If left unresolved, these vulnerabilities could allow criminals to remotely access media and audio conversations from compromised devices. According to Israeli cybersecurity company Check Point, these vulnerabilities could be utilized as a launchpad to carry out RCE attacks by sending a specially crafted audio file. Therefore, there is a need to fix these vulnerabilities. This article will discuss protecting your Android device from these three security vulnerabilities in the audio decoders affecting millions of Android devices.

About Apple Lossless Audio Codec

The vulnerabilities rooted in an audio coding format were originally developed and open-sourced by Apple in 2011. The audio codec format, known as Apple Lossless Audio Codec (ALAC), is used for digital music lossless data compression. 

Since then, various third-party vendors like MediaTek and Qualcomm have incorporated the Apple-supplied audio codec implementation as a cornerstone for their audio decoders. While Apple has consistently patched and rectified security flaws in ALAC proprietary versions, the open-source code variant has not received any update since it was uploaded to GitHub 11 years ago. 

List Of Security Vulnerabilities In The Audio Decoders

The vulnerabilities detected by Check Point are relevant to the ported ALAC code. One of these is found in Qualcomm chipsets and two in MediaTek.

  • CVE-2021-0674 (MediaTek): This vulnerability is due to improper input validation in Apple lossless decoder that leads to information disclosure without user interaction.
  • CVE-2021-0675 (MediaTek): It’s a local privilege escalation flaw in Apple lossless decoder arising from out-of-bounds write.
  • CVE-2021-30351 (Qualcomm): It’s out-of-bounds memory access due to improper validation of the number of frames passed during music playback.

Summary Of Security Vulnerabilities In The Audio Decoders

Here are summaries of all three security vulnerabilities in the audio decoder.

CVE-2021-0674

In the ALAC decoder, there is a possible out-of-bounds read due to incorrect bounds check. It could lead to local information disclosure without requiring additional privileges. Moreover, user interaction is not required for exploitation.

CVECVE-2021-0674
Title Improper input validation in ALAC decoder
CWECWE-20 Improper Input Validation
Vulnerability TypeID
Base Score5.5
SeverityMedium
VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack Vector (AV)Local
Attack Complexity (AC)Low
Privilege Required (PR)None
User Interaction (UI)None
ScopeUnchanged
Confidentiality (C)High
Integrity (I)None
availability (a)None
Affected ChipsetsMT6570, MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6755, MT6755S, MT6757, MT6757C, MT6757CD, MT6757CH, MT6758, MT6761, MT6763, MT6765, MT6768, MT6771, MT6779, MT6781, MT6785, MT6797, MT6799, MT6833, MT6853, MT6853T, MT6873, MT6877, MT6883, MT6885, MT6889, MT6893, MT8163, MT8167, MT8167S, MT8168, MT8173, MT8175, MT8176, MT8183, MT8185, MT8195, MT8321, MT8362A, MT8365, MT8385, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797
Affected Software VersionsAndroid 8.1, 9.0, 10.0, 11.0

CVE-2021-0675

In the ALAC decoder, there is a possible out-of-bounds write due to incorrect bounds check. It could lead to local privilege escalation without requiring additional execution privileges. Moreover, user interaction is not required for exploitation.

CVECVE-2021-0675
Title Local privilege escalation flaw in Apple lossless decode
CWECWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
Vulnerability TypeEoP
Base Score7.8
SeverityHigh
VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV)Local
Attack Complexity (AC)Low
Privilege Required (PR)Low
User Interaction (UI)None
ScopeUnchanged
Confidentiality (C)High
Integrity (I)High
availability (a)High
Affected ChipsetsMT6570, MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6755, MT6755S, MT6757, MT6757C, MT6757CD, MT6757CH, MT6758, MT6761, MT6763, MT6765, MT6768, MT6771, MT6779, MT6781, MT6785, MT6797, MT6799, MT6833, MT6853, MT6853T, MT6873, MT6877, MT6883, MT6885, MT6889, MT6893, MT8163, MT8167, MT8167S, MT8168, MT8173, MT8175, MT8176, MT8183, MT8185, MT8195, MT8321, MT8362A, MT8365, MT8385, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797
Affected Software VersionsAndroid 8.1, 9.0, 10.0, 11.0

CVE-2021-30351

An out of bounds memory access can happen due to improper validation of a number of frames passed during music playback in Snapdragon Compute, Snapdragon Auto, Snapdragon Consumer IoT, Snapdragon Connectivity, Snapdragon mobile, Snapdragon Industrial IoT, Snapdragon Wearables, Snapdragon Voice & Music, Snapdragon Wire Infrastructure and Networking.

Associated CVE IDCVE-2021-30351
DescriptionA out-of-bounds memory access vulnerability in ALAC decoder
CVSS Score7.5 High
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV)Network
Attack Complexity (AC)Low
Privilege Required (PR)None
User Interaction (UI)None
ScopeUnchanged
Confidentiality (C)High
Integrity (I)High
availability (a)High
Affected ChipsetsMT6570, MT6580, MT6735, MT6737, MT6739, MT6750, MT6750S, MT6753, MT6755, MT6755S, MT6757, MT6757C, MT6757CD, MT6757CH, MT6758, MT6761, MT6763, MT6765, MT6768, MT6771, MT6779, MT6781, MT6785, MT6797, MT6799, MT6833, MT6853, MT6853T, MT6873, MT6877, MT6883, MT6885, MT6889, MT6893, MT8163, MT8167, MT8167S, MT8168, MT8173, MT8175, MT8176, MT8183, MT8185, MT8195, MT8321, MT8362A, MT8365, MT8385, MT8765, MT8766, MT8768, MT8786, MT8788, MT8789, MT8791, MT8797
Affected Software VersionsAndroid 8.1, 9.0, 10.0, 11.0

Tips To Secure Your Android Phone

Here are some tips to secure your android devices.

  1. Install a reputable security app: There are many security apps available on the Google Play Store that can help you protect your device from malware and other threats. Look for an app that offers features like virus scanning, real-time protection, and remote locking or wiping in case your device is lost or stolen.
  2. Keep your software up to date: Keeping your Android operating system and apps up to date is important for security as it helps fix known vulnerabilities that could be exploited by hackers. To check for updates, go to Settings > About Phone > System Updates.
  3. Be cautious when downloading apps: Only download apps from trusted sources like the Google Play Store. Be sure to read reviews and check permissions before installing any app, especially if it’s from a third-party store or website.
  4. Don’t click on links in suspicious emails or texts: Malicious links can often be found in unsolicited emails and texts from unknown senders. If you receive a message with a link from someone you don’t know, don’t click on it.
  5. Avoid public Wi-Fi networks: Public Wi-Fi networks are often not secure, meaning that anyone on the same network could potentially intercept the data you’re sending or receiving. If you need to use public Wi-Fi, be sure to connect to a VPN first.
  6. Back up your data: In case your device is lost or stolen, it’s important to have a backup of your data. You can back up your data to the cloud or to an external hard drive.
  7. Use a secure browser: When browsing the web on your Android device, be sure to use a secure browser that offers features like incognito mode and built-in security protection. Some popular secure browsers include Firefox Focus and Chrome Incognito Mode.

By following these tips, you can help keep your Android device safe from potential threats

We hope this post will help you know about Three Security Vulnerabilities in the Audio Decoders that Affects Millions of Android Devices. Please share this post and help to secure the digital world. Visit our social media page on FacebookLinkedInTwitterTelegramTumblr, & Medium and subscribe to receive updates like this. 

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Arun KL

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