Melhorias na segurança

O Android está sempre melhorando as ofertas e as capacidades de segurança. Confira as listas de melhorias por versão no painel de navegação à esquerda.

Android 14

Every Android release includes dozens of security enhancements to protect users. Here are some of the major security enhancements available in Android 14:

  • Hardware-assisted AddressSanitizer (HWASan), introduced in Android 10, is a memory error detection tool similar to AddressSanitizer. Android 14 brings significant improvements to HWASan. Learn how it helps prevent bugs from making it into Android releases, HWAddressSanitizer
  • In Android 14, starting with apps that share location data with third-parties, the system runtime permission dialog now includes a clickable section that highlights the app's data-sharing practices, including information such as why an app may decide to share data with third parties.
  • Android 12 introduced an option to disable 2G support at the modem level, which protects users from the inherent security risk from 2G's obsolete security model. Recognizing how critical disabling 2G could be for enterprise customers, Android 14 enables this security feature in Android Enterprise, introducing support for IT admins to restrict the ability of a managed device to downgrade to 2G connectivity.
  • Added support to reject null-ciphered cellular connections, ensuring that circuit-switched voice and SMS traffic is always encrypted and protected from passive over-the-air interception. Learn more about Android's program to harden cellular connectivity.
  • Added support for multiple IMEIs
  • Since Android 14, AES-HCTR2 is the preferred mode of filenames encryption for devices with accelerated cryptography instructions.
  • Cellular connectivity
  • Documentation added for Android Safety Center
  • If your app targets Android 14 and uses Dynamic Code Loading (DCL), all dynamically-loaded files must be marked as read-only. Otherwise, the system throws an exception. We recommend that apps avoid dynamically loading code whenever possible, as doing so greatly increases the risk that an app can be compromised by code injection or code tampering.

Check out our full AOSP release notes and the Android Developer features and changes list.

Android 13

Every Android release includes dozens of security enhancements to protect users. Here are some of the major security enhancements available in Android 13:

  • Android 13 adds multi-document presentation support. This new Presentation Session interface enables an app to do a multi-document presentation, something which isn't possible with the existing API. For further information, refer to Identity Credential
  • In Android 13, intents originating from external apps are delivered to an exported component if and only if the intents match their declared intent-filter elements.
  • Open Mobile API (OMAPI) is a standard API used to communicate with a device's Secure Element. Before Android 13, only apps and framework modules had access to this interface. By converting it to a vendor stable interface, HAL modules are also capable of communicating with the secure elements through the OMAPI service. For more information, see OMAPI Vendor Stable Interface.
  • As of Android 13-QPR, shared UIDs are deprecated. Users of Android 13 or higher should put the line `android:sharedUserMaxSdkVersion="32"` in their manifest. This entry prevents new users from getting a shared UID. For further information on UIDs, see App signing.
  • Android 13 added support Keystore symmetric cryptographic primitives such as AES (Advanced Encryption Standard), HMAC (Keyed-Hash Message Authentication Code), and asymmetric cryptographic algorithms (including Elliptic Curve, RSA2048, RSA4096, and Curve 25519)
  • Android 13 (API level 33) and higher supports a runtime permission for sending non-exempt notifications from an app. This gives users control over which permission notifications they see.
  • Added per-use prompt for apps requesting access to all device logs, giving users the ability to allow or deny access.
  • introduced the Android Virtualization Framework (AVF), which brings together different hypervisors under one framework with standardized APIs. It provides secure and private execution environments for executing workloads isolated by hypervisor.
  • Introduced APK signature scheme v3.1 All new key rotations that use apksigner use the v3.1 signature scheme by default to target rotation for Android 13 and higher.

Check out our full AOSP release notes and the Android Developer features and changes list.

Android 12

Every Android release includes dozens of security enhancements to protect users. Here are some of the major security enhancements available in Android 12:

  • Android 12 introduces the BiometricManager.Strings API, which provides localized strings for apps that use BiometricPrompt for authentication. These strings are intended to be device-aware and provide more specificity about which authentication types might be used. Android 12 also includes support for under-display fingerprint sensors
  • Support added for under-display fingerprint sensors
  • Introduction of the Fingerprint Android Interface Definition Language (AIDL)
  • Support for new Face AIDL
  • Introduction of Rust as a language for platform development
  • The option for users to grant access only to their approximate location added
  • Added Privacy indicators on the status bar when an app is using the camera or microphone
  • Android's Private Compute Core (PCC)
  • Added an option to disable 2G support

Android 11

Every Android release includes dozens of security enhancements to protect users. For a list of some of the major security enhancements available in Android 11, see the Android Release Notes.

Android 10

Every Android release includes dozens of security enhancements to protect users. Android 10 includes several security and privacy enhancements. See the Android 10 release notes for a complete list of changes in Android 10.

Security

BoundsSanitizer

Android 10 deploys BoundsSanitizer (BoundSan) in Bluetooth and codecs. BoundSan uses UBSan's bounds sanitizer. This mitigation is enabled on a per-module level. It helps keep critical components of Android secure and shouldn't be disabled. BoundSan is enabled in the following codecs:

  • libFLAC
  • libavcdec
  • libavcenc
  • libhevcdec
  • libmpeg2
  • libopus
  • libvpx
  • libspeexresampler
  • libvorbisidec
  • libaac
  • libxaac

Execute-only memory

By default, executable code sections for AArch64 system binaries are marked execute-only (nonreadable) as a hardening mitigation against just-in-time code reuse attacks. Code that mixes data and code together and code that purposefully inspects these sections (without first remapping the memory segments as readable) no longer functions. Apps with a target SDK of Android 10 (API level 29 or higher) are impacted if the app attempts to read code sections of execute-only memory (XOM) enabled system libraries in memory without first marking the section as readable.

Extended access

Trust agents, the underlying mechanism used by tertiary authentication mechanisms such as Smart Lock, can only extend unlock in Android 10. Trust agents can no longer unlock a locked device and can only keep a device unlocked for a maximum of four hours.

Face authentication

Face authentication allows users to unlock their device simply by looking at the front of their device. Android 10 adds support for a new face authentication stack that can securely process camera frames, preserving security and privacy during face authentication on supported hardware. Android 10 also provides an easy way for security-compliant implementations to enable app integration for transactions such as online banking or other services.

Integer Overflow Sanitization

Android 10 enables Integer Overflow Sanitization (IntSan) in software codecs. Ensure that playback performance is acceptable for any codecs that aren't supported in the device's hardware. IntSan is enabled in the following codecs:

  • libFLAC
  • libavcdec
  • libavcenc
  • libhevcdec
  • libmpeg2
  • libopus
  • libvpx
  • libspeexresampler
  • libvorbisidec

Modular system components

Android 10 modularizes some Android system components and enables them to be updated outside of the normal Android release cycle. Some modules include:

OEMCrypto

Android 10 uses OEMCrypto API version 15.

Scudo

Scudo is a dynamic user-mode memory allocator designed to be more resilient against heap-related vulnerabilities. It provides the standard C allocation and deallocation primitives, as well as the C++ primitives.

ShadowCallStack

ShadowCallStack (SCS) is an LLVM instrumentation mode that protects against return address overwrites (like stack buffer overflows) by saving a function's return address to a separately allocated ShadowCallStack instance in the function prolog of nonleaf functions and loading the return address from the ShadowCallStack instance in the function epilog.

WPA3 and Wi-Fi Enhanced Open

Android 10 adds support for the Wi-Fi Protected Access 3 (WPA3) and Wi-Fi Enhanced Open security standards to provide better privacy and robustness against known attacks.

Privacy

App access when targeting Android 9 or lower

If your app runs on Android 10 or higher but targets Android 9 (API level 28) or lower, the platform applies the following behavior:

  • If your app declares a <uses-permission> element for either ACCESS_FINE_LOCATION or ACCESS_COARSE_LOCATION, the system automatically adds a <uses-permission> element for ACCESS_BACKGROUND_LOCATION during installation.
  • If your app requests either ACCESS_FINE_LOCATION or ACCESS_COARSE_LOCATION, the system automatically adds ACCESS_BACKGROUND_LOCATION to the request.

Background activity restrictions

Starting in Android 10, the system places restrictions on starting activities from the background. This behavior change helps minimize interruptions for the user and keeps the user more in control of what's shown on their screen. As long as your app starts activities as a direct result of user interaction, your app most likely isn't affected by these restrictions.
To learn more about the recommended alternative to starting activities from the background, see the guide on how to alert users of time-sensitive events in your app.

Camera metadata

Android 10 changes the breadth of information that the getCameraCharacteristics() method returns by default. In particular, your app must have the CAMERA permission in order to access potentially device-specific metadata that is included in this method's return value.
To learn more about these changes, see the section about camera fields that require permission.

Clipboard data

Unless your app is the default input method editor (IME) or is the app that currently has focus, your app cannot access clipboard data on Android 10 or higher.

Device location

To support the additional control that users have over an app's access to location information, Android 10 introduces the ACCESS_BACKGROUND_LOCATION permission.
Unlike the ACCESS_FINE_LOCATION and ACCESS_COARSE_LOCATION permissions, the ACCESS_BACKGROUND_LOCATION permission only affects an app's access to location when it runs in the background. An app is considered to be accessing location in the background unless one of the following conditions is satisfied:

  • An activity belonging to the app is visible.
  • The app is running a foreground service that has declared a foreground service type of location.
    To declare the foreground service type for a service in your app, set your app's targetSdkVersion or compileSdkVersion to 29 or higher. Learn more about how foreground services can continue user-initiated actions that require access to location.

External storage

By default, apps targeting Android 10 and higher are given scoped access into external storage, or scoped storage. Such apps can see the following types of files within an external storage device without needing to request any storage-related user permissions:

To learn more about scoped storage, as well as how to share, access, and modify files that are saved on external storage devices, see the guides on how to manage files in external storage and access and modify media files.

MAC address randomization

On devices that run Android 10 or higher, the system transmits randomized MAC addresses by default.
If your app handles an enterprise use case, the platform provides APIs for several operations related to MAC addresses:

  • Obtain randomized MAC address: Device owner apps and profile owner apps can retrieve the randomized MAC address assigned to a specific network by calling getRandomizedMacAddress().
  • Obtain actual, factory MAC address: Device owner apps can retrieve a device's actual hardware MAC address by calling getWifiMacAddress(). This method is useful for tracking fleets of devices.

Non-resettable device identifiers

Starting in Android 10, apps must have the READ_PRIVILEGED_PHONE_STATE privileged permission in order to access the device's non-resettable identifiers, which include both IMEI and serial number.

If your app doesn't have the permission and you try asking for information about non-resettable identifiers anyway, the platform's response varies based on target SDK version:

  • If your app targets Android 10 or higher, a SecurityException occurs.
  • If your app targets Android 9 (API level 28) or lower, the method returns null or placeholder data if the app has the READ_PHONE_STATE permission. Otherwise, a SecurityException occurs.

Physical activity recognition

Android 10 introduces the android.permission.ACTIVITY_RECOGNITION runtime permission for apps that need to detect the user's step count or classify the user's physical activity, such as walking, biking, or moving in a vehicle. This is designed to give users visibility of how device sensor data is used in Settings.
Some libraries within Google Play services, such as the Activity Recognition API and the Google Fit API, don't provide results unless the user has granted your app this permission.
The only built-in sensors on the device that require you to declare this permission are the step counter and step detector sensors.
If your app targets Android 9 (API level 28) or lower, the system auto-grants the android.permission.ACTIVITY_RECOGNITION permission to your app, as needed, if your app satisfies each of the following conditions:

  • The manifest file includes the com.google.android.gms.permission.ACTIVITY_RECOGNITION permission.
  • The manifest file doesn't include the android.permission.ACTIVITY_RECOGNITION permission.

If the system-auto grants the android.permission.ACTIVITY_RECOGNITION permission, your app retains the permission after you update your app to target Android 10. However, the user can revoke this permission at any time in system settings.

/proc/net filesystem restrictions

On devices that run Android 10 or higher, apps cannot access /proc/net, which includes information about a device's network state. Apps that need access to this information, such as VPNs, should use the NetworkStatsManager or ConnectivityManager class.

Permission groups removed from UI

As of Android 10, apps cannot look up how permissions are grouped in the UI.

Removal of contacts affinity

Starting in Android 10, the platform doesn't keep track of contacts affinity information. As a result, if your app conducts a search on the user's contacts, the results aren't ordered by frequency of interaction.
The guide about ContactsProvider contains a notice describing the specific fields and methods that are obsolete on all devices starting in Android 10.

Restricted access to screen contents

To protect users' screen contents, Android 10 prevents silent access to the device's screen contents by changing the scope of the READ_FRAME_BUFFER, CAPTURE_VIDEO_OUTPUT, and CAPTURE_SECURE_VIDEO_OUTPUT permissions. As of Android 10, these permissions are signature-access only.
Apps that need to access the device's screen contents should use the MediaProjection API, which displays a prompt asking the user to provide consent.

USB device serial number

If your app targets Android 10 or higher, your app cannot read the serial number until the user has granted your app permission to access the USB device or accessory.
To learn more about working with USB devices, see the guide on how to configure USB hosts.

Wi-Fi

Apps targeting Android 10 or higher cannot enable or disable Wi-Fi. The WifiManager.setWifiEnabled() method always returns false.
If you need to prompt users to enable and disable Wi-Fi, use a settings panel.

Restrictions on direct access to configured Wi-Fi networks

To protect user privacy, manual configuration of the list of Wi-Fi networks is restricted to system apps and device policy controllers (DPCs). A given DPC can be either the device owner or the profile owner.
If your app targets Android 10 or higher, and it isn't a system app or a DPC, then the following methods don't return useful data:

Android 9

Every Android release includes dozens of security enhancements to protect users. For a list of some of the major security enhancements available in Android 9, see the Android Release Notes.

Android 8

Cada versão do Android inclui dezenas de melhorias de segurança para proteger os usuários. Confira algumas das principais melhorias de segurança disponíveis no Android 8.0:

  • Criptografia. Foi adicionado suporte para a exclusão de chaves no perfil de trabalho.
  • Inicialização verificada. Inicialização verificada do Android (AVB, na sigla em inglês) adicionada. Verificada A base de código de inicialização com suporte à proteção contra reversão para uso em carregadores de inicialização foi adicionada ao AOSP. Recomendar suporte ao carregador de inicialização para proteção contra reversão para o HLOS. Recomendar que os gerenciadores de inicialização só possam ser desbloqueados com a interação física do usuário com o dispositivo.
  • Tela de bloqueio. Foi adicionado suporte ao uso de dispositivos resistentes a adulterações. para verificar a credencial da tela de bloqueio.
  • KeyStore. Chave obrigatória atestado para todos os dispositivos que vêm com o Android 8.0 ou versões mais recentes. ID adicionado suporte a atestados para melhorar o registro sem toque.
  • Sandbox: Mais sandbox rígido para muitos componentes usando a interface padrão do Project Treble entre o framework e os componentes específicos do dispositivo. A filtragem seccomp foi aplicada a todos os apps não confiáveis para reduzir a superfície de ataque do kernel. A WebView agora é executada em um processo isolado com acesso muito limitado ao restante do sistema.
  • Aumento da proteção do kernel. Implementação de usercopy reforçada, emulação de PAN, somente leitura após a inicialização e KASLR.
  • Aumento da proteção do espaço do usuário. A CFI foi implementada para a pilha de mídia. As sobreposições de aplicativos não podem mais cobrir janelas críticas do sistema, e os usuários podem descartá-las.
  • Atualização do SO de streaming. Atualizações ativadas em dispositivos com pouco espaço em disco.
  • Instalar apps desconhecidos. Os usuários devem conceder permissão para instalar apps de uma fonte que não seja uma app store primária.
  • Privacidade. O ID do Android (SSAID, na sigla em inglês) tem um valor diferente para cada app e cada usuário no dispositivo. Para apps de navegador da Web, o ID do cliente Widevine retorna um valor diferente para cada nome de pacote de app e origem da Web. O net.hostname agora está vazio, e o cliente DHCP não envia mais um nome de host. android.os.Build.SERIAL foi substituído pelo API Build.SERIAL protegida por uma permissão controlada pelo usuário. Endereço MAC aprimorado randomização em alguns chipsets.

No Android 7

Every Android release includes dozens of security enhancements to protect users. Here are some of the major security enhancements available in Android 7.0:

  • File-based encryption. Encrypting at the file level, instead of encrypting the entire storage area as a single unit, better isolates and protects individual users and profiles (such as personal and work) on a device.
  • Direct Boot. Enabled by file-based encryption, Direct Boot allows certain apps such as alarm clock and accessibility features to run when device is powered on but not unlocked.
  • Verified Boot. Verified Boot is now strictly enforced to prevent compromised devices from booting; it supports error correction to improve reliability against non-malicious data corruption.
  • SELinux. Updated SELinux configuration and increased seccomp coverage further locks down the Application Sandbox and reduces attack surface.
  • Library load-order randomization and improved ASLR. Increased randomness makes some code-reuse attacks less reliable.
  • Kernel hardening. Added additional memory protection for newer kernels by marking portions of kernel memory as read-only, restricting kernel access to userspace addresses and further reducing the existing attack surface.
  • APK signature scheme v2. Introduced a whole-file signature scheme that improves verification speed and strengthens integrity guarantees.
  • Trusted CA store. To make it easier for apps to control access to their secure network traffic, user-installed certificate authorities and those installed through Device Admin APIs are no longer trusted by default for apps targeting API Level 24+. Additionally, all new Android devices must ship with the same trusted CA store.
  • Network Security Config. Configure network security and TLS through a declarative configuration file.

Android 6

Every Android release includes dozens of security enhancements to protect users. Here are some of the major security enhancements available in Android 6.0:

  • Runtime Permissions. Apps request permissions at runtime instead of being granted at App install time. Users can toggle permissions on and off for both M and pre-M apps.
  • Verified Boot. A set of cryptographic checks of system software are conducted prior to execution to ensure the phone is healthy from the bootloader all the way up to the operating system.
  • Hardware-Isolated Security. New Hardware Abstraction Layer (HAL) used by Fingerprint API, Lockscreen, Device Encryption, and Client Certificates to protect keys against kernel compromise and/or local physical attacks
  • Fingerprints. Devices can now be unlocked with just a touch. Developers can also take advantage of new APIs to use fingerprints to lock and unlock encryption keys.
  • SD Card Adoption. Removable media can be adopted to a device and expand available storage for app local data, photos, videos, etc., but still be protected by block-level encryption.
  • Clear Text Traffic. Developers can use a new StrictMode to make sure their app doesn't use cleartext.
  • System Hardening. Hardening of the system via policies enforced by SELinux. This offers better isolation between users, IOCTL filtering, reduce threat of exposed services, further tightening of SELinux domains, and extremely limited /proc access.
  • USB Access Control: Users must confirm to allow USB access to files, storage, or other functionality on the phone. Default is now charge only with access to storage requiring explicit approval from the user.

Android 5

5.0

Every Android release includes dozens of security enhancements to protect users. Here are some of the major security enhancements available in Android 5.0:

  • Encrypted by default. On devices that ship with L out-of-the-box, full disk encryption is enabled by default to improve protection of data on lost or stolen devices. Devices that update to L can be encrypted in Settings > Security .
  • Improved full disk encryption. The user password is protected against brute-force attacks using scrypt and, where available, the key is bound to the hardware keystore to prevent off-device attacks. As always, the Android screen lock secret and the device encryption key are not sent off the device or exposed to any application.
  • Android sandbox reinforced with SELinux . Android now requires SELinux in enforcing mode for all domains. SELinux is a mandatory access control (MAC) system in the Linux kernel used to augment the existing discretionary access control (DAC) security model. This new layer provides additional protection against potential security vulnerabilities.
  • Smart Lock. Android now includes trustlets that provide more flexibility for unlocking devices. For example, trustlets can allow devices to be unlocked automatically when close to another trusted device (through NFC, Bluetooth) or being used by someone with a trusted face.
  • Multi user, restricted profile, and guest modes for phones and tablets. Android now provides for multiple users on phones and includes a guest mode that can be used to provide easy temporary access to your device without granting access to your data and apps.
  • Updates to WebView without OTA. WebView can now be updated independent of the framework and without a system OTA. This allows for faster response to potential security issues in WebView.
  • Updated cryptography for HTTPS and TLS/SSL. TLSv1.2 and TLSv1.1 is now enabled, Forward Secrecy is now preferred, AES-GCM is now enabled, and weak cipher suites (MD5, 3DES, and export cipher suites) are now disabled. See https://developer.android.com/reference/javax/net/ssl/SSLSocket.html for more details.
  • non-PIE linker support removed. Android now requires all dynamically linked executables to support PIE (position-independent executables). This enhances Android's address space layout randomization (ASLR) implementation.
  • FORTIFY_SOURCE improvements. The following libc functions now implement FORTIFY_SOURCE protections: stpcpy(), stpncpy(), read(), recvfrom(), FD_CLR(), FD_SET(), and FD_ISSET(). This provides protection against memory-corruption vulnerabilities involving those functions.
  • Security Fixes. Android 5.0 also includes fixes for Android-specific vulnerabilities. Information about these vulnerabilities has been provided to Open Handset Alliance members, and fixes are available in Android Open Source Project. To improve security, some devices with earlier versions of Android may also include these fixes.

Android 4 e anterior

Every Android release includes dozens of security enhancements to protect users. The following are some of the security enhancements available in Android 4.4:

  • Android sandbox reinforced with SELinux. Android now uses SELinux in enforcing mode. SELinux is a mandatory access control (MAC) system in the Linux kernel used to augment the existing discretionary access control (DAC) based security model. This provides additional protection against potential security vulnerabilities.
  • Per User VPN. On multi-user devices, VPNs are now applied per user. This can allow a user to route all network traffic through a VPN without affecting other users on the device.
  • ECDSA Provider support in AndroidKeyStore. Android now has a keystore provider that allows use of ECDSA and DSA algorithms.
  • Device Monitoring Warnings. Android provides users with a warning if any certificate has been added to the device certificate store that could allow monitoring of encrypted network traffic.
  • FORTIFY_SOURCE. Android now supports FORTIFY_SOURCE level 2, and all code is compiled with these protections. FORTIFY_SOURCE has been enhanced to work with clang.
  • Certificate Pinning. Android 4.4 detects and prevents the use of fraudulent Google certificates used in secure SSL/TLS communications.
  • Security Fixes. Android 4.4 also includes fixes for Android-specific vulnerabilities. Information about these vulnerabilities has been provided to Open Handset Alliance members and fixes are available in Android Open Source Project. To improve security, some devices with earlier versions of Android may also include these fixes.

Cada versão do Android inclui dezenas de melhorias de segurança para proteger os usuários. Confira a seguir algumas das melhorias de segurança no Android 4.3:

  • Sandbox do Android reforçado com o SELinux. Esta versão fortalece o sandbox do Android usando o SELinux sistema de controle de acesso obrigatório (MAC, na sigla em inglês) no kernel do Linux. SELinux o reforço é invisível para usuários e desenvolvedores e aumenta a robustez com o modelo de segurança atual do Android, mantendo a compatibilidade com aplicativos existentes. Para garantir a compatibilidade contínua, essa versão permite o uso do SELinux em um modo permissivo. Esse modo registra todas as violações de políticas, mas não quebra apps nem afeta o comportamento do sistema.
  • Nenhum programa setuid ou setgid. Suporte adicionado para recursos do sistema de arquivos aos arquivos de sistema do Android e removeu todos os programas setuid ou setgid. Isso reduz a superfície de ataque raiz e a probabilidade de possíveis vulnerabilidades de segurança.
  • Autenticação do ADB. No Android 4.2.2 e versões mais recentes, as conexões com o ADB são autenticadas com um par de chaves RSA. Isso impede o uso não autorizado do ADB quando o invasor tem acesso físico a um dispositivo.
  • Restringir o Setuid de apps Android. A partição /system agora é montada com o flag nosuid para processos gerados por zigotos, impedindo que apps Android executem programas setuid. Isso reduz a superfície de ataque raiz e a probabilidade de possíveis vulnerabilidades de segurança.
  • Limite de recursos. O zigoto do Android e o adb agora usam prctl(PR_CAPBSET_DROP) para soltar recursos desnecessários antes de executar os aplicativos. Isso impede que apps Android e apps iniciados pelo shell adquiram recursos privilegiados.
  • Provedor AndroidKeyStore. O Android agora tem um provedor de keystore que permite para criar chaves de uso exclusivo. Isso fornece aos apps com uma API para criar ou armazenar chaves privadas que não podem ser usadas e outros apps.
  • KeyChain isBoundKeyAlgorithm. A API Keychain agora oferece um método (isBoundKeyType) que permite que os apps confirmem que as chaves do sistema estão vinculadas a uma raiz de hardware confiável para o dispositivo. Isso fornece um local para criar ou armazenar chaves privadas que não podem ser exportadas dispositivo, mesmo em caso de comprometimento de raiz.
  • NO_NEW_PRIVS. O zygote do Android agora usa prctl(PR_SET_NO_NEW_PRIVS) para bloquear a adição de novos privilégios antes da execução do código do app. Isso impede que apps Android executem operações que podem elevar privilégios através do execve. Isso requer a versão 3.5 do kernel do Linux ou mais recente.
  • Melhorias no FORTIFY_SOURCE. FORTIFY_SOURCE ativado no Android x86 e MIPS e fortificadas strchr(), strrchr(), strlen() e umask(). Isso pode detectar possíveis vulnerabilidades de corrupção de memória ou constantes de string.
  • Proteções de realocação. Relocalizações somente leitura (relro) foram ativadas para executáveis vinculados de forma estática, e todas as relocalizações de texto no código do Android foram removidas. Isso fornece uma defesa em profundidade contra possíveis vulnerabilidades de corrupção de memória.
  • Melhoramos o EntropyMixer. O EntropyMixer agora grava entropia no desligamento ou reinicialização, além de misturas periódicas. Isso permite a retenção de todos gerada quando os dispositivos estão ligados e é especialmente útil para dispositivos que são reinicializados imediatamente após o provisionamento.
  • Correções de segurança. O Android 4.3 também inclui correções de vulnerabilidades específicas do Android. Foram fornecidas informações sobre essas vulnerabilidades aos membros do Open Handset Alliance, e as correções estão disponíveis no Android Open Source Project. Para melhorar a segurança, alguns dispositivos com versões anteriores do Android também podem incluir essas correções.

O Android fornece um modelo de segurança de várias camadas descrito na Visão geral de segurança do Android . Cada atualização do Android inclui dezenas de aprimoramentos de segurança para proteger os usuários. A seguir estão alguns dos aprimoramentos de segurança introduzidos no Android 4.2:

  • Verificação do aplicativo - os usuários podem optar por ativar "Verificar aplicativos" e fazer com que os aplicativos sejam examinados por um verificador de aplicativos antes da instalação. A verificação do aplicativo pode alertar o usuário se ele tentar instalar um aplicativo que pode ser prejudicial; se um aplicativo for especialmente ruim, pode bloquear a instalação.
  • Mais controle de SMS premium - o Android fornecerá uma notificação se um aplicativo tentar enviar SMS para um código curto que usa serviços premium que podem causar cobranças adicionais. O usuário pode optar por permitir que o aplicativo envie a mensagem ou bloqueá-la.
  • Always-on VPN - A VPN pode ser configurada para que os aplicativos não tenham acesso à rede até que uma conexão VPN seja estabelecida. Isso impede que os aplicativos enviem dados por outras redes.
  • Fixação de certificados - as bibliotecas principais do Android agora oferecem suporte à fixação de certificados . Os domínios fixados receberão uma falha de validação de certificado se o certificado não for encadeado a um conjunto de certificados esperados. Isso protege contra possível comprometimento das Autoridades de Certificação.
  • Exibição aprimorada de permissões do Android - As permissões foram organizadas em grupos que são mais facilmente compreendidos pelos usuários. Durante a revisão das permissões, o usuário pode clicar na permissão para ver informações mais detalhadas sobre a permissão.
  • installd hardening - O daemon installd não é executado como usuário root, reduzindo a potencial superfície de ataque para escalonamento de privilégios de root.
  • Init script hardening - scripts init agora aplicam a semântica O_NOFOLLOW para evitar ataques relacionados a links simbólicos.
  • FORTIFY_SOURCE - Android agora implementa FORTIFY_SOURCE . Isso é usado por bibliotecas e aplicativos do sistema para evitar corrupção de memória.
  • Configuração padrão do ContentProvider - os aplicativos direcionados à API de nível 17 terão "exportar" definido como "falso" por padrão para cada provedor de conteúdo , reduzindo a superfície de ataque padrão para aplicativos.
  • Criptografia - Modificadas as implementações padrão de SecureRandom e Cipher.RSA para usar OpenSSL. Adicionado suporte SSL Socket para TLSv1.1 e TLSv1.2 usando OpenSSL 1.0.1
  • Correções de segurança - Bibliotecas de código aberto atualizadas com correções de segurança incluem WebKit, libpng, OpenSSL e LibXML. O Android 4.2 também inclui correções para vulnerabilidades específicas do Android. As informações sobre essas vulnerabilidades foram fornecidas aos membros da Open Handset Alliance e as correções estão disponíveis no Android Open Source Project. Para melhorar a segurança, alguns dispositivos com versões anteriores do Android também podem incluir essas correções.

Android provides a multi-layered security model described in the Android Security Overview. Each update to Android includes dozens of security enhancements to protect users. The following are some of the security enhancements introduced in Android versions 1.5 through 4.1:

Android 1.5
  • ProPolice to prevent stack buffer overruns (-fstack-protector)
  • safe_iop to reduce integer overflows
  • Extensions to OpenBSD dlmalloc to prevent double free() vulnerabilities and to prevent chunk consolidation attacks. Chunk consolidation attacks are a common way to exploit heap corruption.
  • OpenBSD calloc to prevent integer overflows during memory allocation
Android 2.3
  • Format string vulnerability protections (-Wformat-security -Werror=format-security)
  • Hardware-based No eXecute (NX) to prevent code execution on the stack and heap
  • Linux mmap_min_addr to mitigate null pointer dereference privilege escalation (further enhanced in Android 4.1)
Android 4.0
Address Space Layout Randomization (ASLR) to randomize key locations in memory
Android 4.1
  • PIE (Position Independent Executable) support
  • Read-only relocations / immediate binding (-Wl,-z,relro -Wl,-z,now)
  • dmesg_restrict enabled (avoid leaking kernel addresses)
  • kptr_restrict enabled (avoid leaking kernel addresses)