Google has released the April 2021 Android Security Bulletin, giving carriers and device makers a fresh set of patches to install. Though Google puts out the Android security patches each month, the job of actually getting the fixes to end users falls on the telcos and/or device manufacturers themselves. Those partners vary in their ability to release the patches in a timely fashion.
The bulletin addresses 36 vulnerabilities, out of which 2 are rated as critical vulnerabilities. The vulnerabilities affect open-source components such as the Android Framework, Android Media Framework, Android System, and Android’s Linux Kernel fork. The vulnerabilities also affect MediaTek and QUALCOMM closed-source components.
The April 2021 bulletin has two security patch levels to provide Android partners with the flexibility to more quickly fix a subset of vulnerabilities that are similar across all Android devices.
- 01-04-2021: Partial security patch level string. This security patch level string indicates that all issues associated with 01-04-2021 (and all previous security patch level strings) are addressed.
- 05-04-2021: Complete security patch level string. This security patch level address all issues associated with the 05-04-2021 security patch level and all previous patch levels.
The most severe of these issues is a critical security vulnerability in the System component that could enable a remote attacker using a specially crafted file to execute arbitrary code within the context of a privileged process. The severity assessment is based on the effect that exploiting the vulnerability would possibly have on an affected device, assuming the platform and service mitigations are turned off for development purposes or if successfully bypassed.
Alongside the bulletin, Google have released a security update to Google devices through an over-the-air (OTA) update. The Google device firmware images have also been released to the Google Developer site. Security patch levels of April 5, 2021 or later address all of these issues.
The tables below contains a list of security vulnerabilities, the Common Vulnerability and Exposures ID (CVE), the assessed severity, and whether or not Google devices are affected. The severity assessment is based on the effect that exploiting the vulnerability would possibly have on an affected device, assuming the platform and service mitigations are disabled for development purposes or if successfully bypassed.
Android and Google Service Mitigation’s
This is a summary of the mitigation’s provided by the Android security platform and service protections such as Google Play Protect. These capabilities reduce the likelihood that security vulnerabilities could be successfully exploited on Android.
- Exploitation for many issues on Android is made more difficult by enhancements in newer versions of the Android platform. All users are encouraged to update to the latest version of Android where possible.
- The Android security team actively monitors for abuse through Google Play Protect and warns users about Potentially Harmful Applications. Google Play Protect is enabled by default on devices with Google Mobile Services, and is especially important for users who install apps from outside of Google Play.
Terminology
You will find different types of vulnerabilities listed. Possible types include:
- RCE – Remote code execution
- EoP – Elevation of privilege
- ID – Information disclosure
- DoS – Denial of service
- N/A – Classification not available
01-04-2021 security patch level—Vulnerability details
Framework
| CVE | References | Type | Severity | Updated AOSP versions |
|---|---|---|---|---|
| CVE-2021-0400 | A-177561690 | EoP | High | 9, 10, 11 |
| CVE-2021-0426 | A-174485572 | EoP | High | 11 |
| CVE-2021-0427 | A-174488848 | EoP | High | 11 |
| CVE-2021-0432 | A-173552790 | EoP | High | 11 |
| CVE-2021-0438 | A-152064592 | EoP | High | 8.1, 9, 10 |
| CVE-2021-0439 | A-174243830 | EoP | High | 11 |
| CVE-2021-0442 | A-174768985 | EoP | High | 11 |
| CVE-2021-0443 | A-170474245 | ID | High | 8.1, 9, 10, 11 |
| CVE-2021-0444 | A-178825358 | ID | High | 8.1, 9, 10, 11 |
Media Framework
The most severe vulnerability in this section could enable a local malicious application to bypass user interaction requirements in order to gain access to additional permissions.
| CVE | References | Type | Severity | Updated AOSP versions |
|---|---|---|---|---|
| CVE-2021-0437 | A-176168330 | EoP | High | 8.1, 9, 10, 11 |
| CVE-2021-0436 | A-176496160 | ID | High | 8.1, 9, 10, 11 |
| CVE-2021-0471 | A-176444786 | ID | High | 8.1, 9, 10, 11 |
System
The most severe vulnerability in this section could enable a remote attacker using a specially crafted file to execute arbitrary code within the context of a privileged process.
| CVE | References | Type | Severity | Updated AOSP versions |
|---|---|---|---|---|
| CVE-2021-0430 | A-178725766 | RCE | Critical | 10, 11 |
| CVE-2021-0429 | A-175074139 | EoP | High | 8.1, 9, 10, 11 |
| CVE-2021-0433 | A-171221090 | EoP | High | 8.1, 9, 10, 11 |
| CVE-2021-0446 | A-172252122 | EoP | High | 11 |
| CVE-2021-0431 | A-174149901 | ID | High | 8.1, 9, 10, 11 |
| CVE-2021-0435 | A-174150451 | ID | High | 8.1, 9, 10, 11 |
Google Play system updates
The following issues are included in Project Mainline components.
| Component | CVE |
|---|---|
| Statsd | CVE-2021-0426, CVE-2021-0427, CVE-2021-0432 |
05-04-2021 security patch level—Vulnerability details
System
The most severe vulnerability in this section could enable a local malicious application to bypass user interaction requirements in order to gain access to additional permissions.
| CVE | References | Type | Severity | Updated AOSP versions |
|---|---|---|---|---|
| CVE-2021-0445 | A-172322502 | EoP | High | 9, 11 |
| CVE-2021-0428 | A-173421434 | ID | High | 10 |
Kernel components
The most severe vulnerability in this section could enable a local attacker using a specially crafted file to execute arbitrary code within the context of a privileged process.
| CVE | References | Type | Severity | Component |
|---|---|---|---|---|
| CVE-2020-15436 | A-174737742 Upstream kernel | EoP | High | Kernel Block Device Subsystem |
| CVE-2020-25705 | A-174737972 Upstream kernel | ID | High | ICMP |
MediaTek components
This vulnerability affects MediaTek components and further details are available directly from MediaTek. The severity assessment of this issue is provided directly by MediaTek.
| CVE | References | Severity | Component |
|---|---|---|---|
| CVE-2021-0468 | A-180427272 M-ALPS05518125 | High | LK |
Qualcomm components
This vulnerability affects Qualcomm components and are described in further detail in the appropriate Qualcomm security bulletin or security alert. The severity assessment of this issue is provided directly by Qualcomm.
| CVE | References | Severity | Component |
|---|---|---|---|
| CVE-2020-11234 | A-170139095 QC-CR#2439497 | High | Kernel |
Qualcomm closed-source components
These vulnerabilities affect Qualcomm closed-source components and are described in further detail in the appropriate Qualcomm security bulletin or security alert. The severity assessment of these issues is provided directly by Qualcomm.
| CVE | References | Severity | Component |
|---|---|---|---|
| CVE-2020-11210 | A-170138788 | Critical | Closed-source component |
| CVE-2020-11191 | A-170138864 | High | Closed-source component |
| CVE-2020-11236 | A-170138748 | High | Closed-source component |
| CVE-2020-11237 | A-170138790 | High | Closed-source component |
| CVE-2020-11242 | A-170138747 | High | Closed-source component |
| CVE-2020-11243 | A-170139096 | High | Closed-source component |
| CVE-2020-11245 | A-170138750 | High | Closed-source component |
| CVE-2020-11246 | A-159482433 | High | Closed-source component |
| CVE-2020-11247 | A-170138749 | High | Closed-source component |
| CVE-2020-11251 | A-170137904 | High | Closed-source component |
| CVE-2020-11252 | A-170138791 | High | Closed-source component |
| CVE-2020-11255 | A-170138865 | High | Closed-source component |
Full details of the April 2021 Android Security Bulletin are available here.
