CVE-2022-20159 in Android
Summary
by MITRE • 06/15/2022
In asn1_ec_pkey_parse of acropora/crypto/asn1_common.c, there is a possible out of bounds read due to an incorrect bounds check. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-210971465References: N/A
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability identified as CVE-2022-20159 represents a critical out-of-bounds read flaw within the Android kernel's cryptographic implementation, specifically within the asn1_ec_pkey_parse function located in acropora/crypto/asn1_common.c. This issue stems from an inadequate bounds check during the parsing of ASN.1 encoded elliptic curve public keys, creating a scenario where maliciously crafted cryptographic data could trigger memory access violations. The vulnerability's classification as a local information disclosure threat indicates that exploitation requires system execution privileges, meaning an attacker must already have elevated access to the device to leverage this weakness. The absence of user interaction requirements for exploitation suggests this could be particularly concerning in scenarios where privilege escalation has already occurred or when the vulnerable system is accessible through other attack vectors.
The technical nature of this vulnerability aligns with CWE-129, which describes improper validation of array index values, and more specifically relates to improper bounds checking in memory operations. The flaw manifests when the cryptographic parsing routine fails to properly validate the boundaries of memory regions during ASN.1 structure processing, potentially allowing an attacker to read memory contents beyond the intended buffer limits. This type of vulnerability falls under the ATT&CK technique T1059.001 for Command and Scripting Interpreter, as exploitation typically requires execution of system-level code that could potentially be used to gather additional information from the device's memory space. The implementation error occurs during the cryptographic key parsing phase where the system attempts to validate elliptic curve public key structures, making it particularly dangerous in environments where cryptographic operations are frequently performed.
The operational impact of CVE-2022-20159 extends beyond simple information disclosure, as it could potentially expose sensitive cryptographic materials or system memory contents that might aid in further attacks. While the vulnerability requires system execution privileges for exploitation, it represents a significant risk in environments where privilege escalation attacks are possible or where the system is already compromised. The affected Android kernel version suggests this vulnerability could impact a wide range of mobile devices and embedded systems that rely on the affected cryptographic libraries, particularly those implementing elliptic curve cryptography for secure communications. The vulnerability's location within the core crypto library means that any application or system component that performs ASN.1 parsing of elliptic curve keys could potentially be affected, creating a broad attack surface that extends across multiple security domains.
Mitigation strategies for CVE-2022-20159 should focus on implementing proper bounds checking mechanisms within the cryptographic parsing routines and ensuring that all memory access operations include adequate validation before buffer access. System administrators should prioritize updating affected Android kernel versions to patches that address the improper bounds check in the asn1_ec_pkey_parse function, as these updates typically include comprehensive fixes for memory safety issues. Additionally, monitoring for unusual memory access patterns or cryptographic parsing failures could help detect exploitation attempts, though such monitoring should be implemented carefully to avoid performance impacts. The vulnerability's classification as a local information disclosure threat means that physical access or prior compromise of system privileges is required for exploitation, but this limitation does not reduce the importance of addressing the underlying memory safety issue. Security teams should also consider implementing runtime protections such as stack canaries or memory corruption detection mechanisms to provide additional defense-in-depth measures against similar vulnerabilities that may exist within the cryptographic subsystem.