CVE-2018-9556 in Android
Summary
by MITRE
In ParsePayloadHeader of payload_metadata.cc, there is a possible out of bounds write due to an integer overflow. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android. Versions: Android-9. Android ID: A-113118184.
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Analysis
by VulDB Data Team • 04/18/2020
The vulnerability identified as CVE-2018-9556 represents a critical security flaw within the Android operating system's handling of payload metadata structures. This issue resides in the ParsePayloadHeader function within the payload_metadata.cc file, which processes update payloads during system maintenance operations. The flaw manifests as an integer overflow condition that can potentially result in out-of-bounds memory write operations, creating a significant vector for privilege escalation attacks.
The technical implementation of this vulnerability stems from improper validation of integer values during payload header parsing. When processing maliciously crafted update payloads, the system fails to adequately check for integer overflow conditions before performing memory allocation calculations. This oversight allows an attacker to manipulate the payload structure in such a way that the calculated buffer size exceeds the intended boundaries, leading to memory corruption. The vulnerability operates at the kernel level within Android's update mechanism, specifically affecting the system's ability to properly validate and process update metadata before installation.
The operational impact of CVE-2018-9556 extends beyond typical exploitation scenarios due to its remote nature and lack of user interaction requirements. An attacker can leverage this vulnerability to achieve full system privilege escalation without needing any additional execution privileges or physical access to the device. The flaw affects Android 9.0 (Pie) and potentially earlier versions, making it a widespread concern across numerous devices. This type of vulnerability directly maps to CWE-190, which describes integer overflow conditions that can lead to memory corruption, and aligns with ATT&CK technique T1068, which covers the exploitation of system privileges for escalation.
Mitigation strategies for this vulnerability require immediate system updates from manufacturers, as the flaw exists within core Android system components that cannot be patched through user applications alone. Device manufacturers must implement proper integer overflow checks in their payload processing routines and ensure that all buffer size calculations are validated against maximum permissible values. Security researchers should monitor for related vulnerabilities in similar payload handling mechanisms across different Android versions and consider implementing additional runtime protections such as stack canaries and address space layout randomization. The vulnerability's classification as a remote privilege escalation vector necessitates comprehensive network security monitoring and immediate patch deployment across all affected Android devices to prevent potential exploitation by malicious actors.