CVE-2022-20162 in Android
Summary
by MITRE • 06/15/2022
In asn1_p256_int of crypto/asn1.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-223492713References: N/A
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability identified as CVE-2022-20162 represents a critical out-of-bounds read flaw within the Android kernel's ASN.1 parsing functionality, specifically within the asn1_p256_int function located in crypto/asn1.c. This issue stems from an incorrect bounds check implementation that fails to properly validate array access boundaries during cryptographic operations involving P256 elliptic curve integers. The vulnerability exists at the intersection of cryptographic processing and memory safety, creating a potential pathway for information disclosure attacks.
The technical implementation flaw manifests when the ASN.1 parser processes elliptic curve cryptography data structures, particularly those involving P256 curve parameters. The incorrect bounds check allows an attacker to manipulate input data in such a way that memory locations beyond the intended array boundaries are accessed. This type of vulnerability falls under CWE-129, which specifically addresses insufficient bounds checking, and can be categorized under the broader ATT&CK technique T1059.001 for command and scripting interpreter. The flaw requires system execution privileges for exploitation, indicating that it operates at a privileged kernel level where it can access sensitive memory regions and potentially extract confidential information from adjacent memory locations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could enable attackers with system-level privileges to extract sensitive cryptographic keys, session data, or other confidential information stored in memory. The local nature of the attack means that exploitation requires an attacker to already possess system-level access or be able to execute code with kernel privileges. This makes the vulnerability particularly concerning in environments where privilege escalation is possible or where attackers can leverage other vulnerabilities to gain system-level access. The Android kernel's cryptographic subsystem is fundamental to secure communications, certificate validation, and cryptographic operations, making this vulnerability a significant threat to the overall security posture of Android devices.
Mitigation strategies for CVE-2022-20162 should focus on implementing proper bounds checking within the ASN.1 parsing routines and ensuring that all memory accesses are validated against proper array boundaries. The fix should involve strengthening the existing bounds check logic in the asn1_p256_int function to prevent out-of-bounds memory access. Security practitioners should also implement robust memory safety mechanisms including stack canaries, address space layout randomization, and compiler-based bounds checking features. Additionally, regular security audits of cryptographic libraries and kernel components should be conducted to identify similar vulnerabilities. The Android security team has addressed this issue through kernel updates, and device manufacturers should ensure timely deployment of these patches to protect against potential exploitation. Organizations should also consider implementing monitoring solutions that can detect anomalous memory access patterns that might indicate exploitation attempts.