CVE-2017-13323 in Android
Summary
by MITRE • 11/28/2024
In String16 of String16.cpp, there is a possible out of bounds write due to an integer overflow. This could lead to local escalation of privilege in an unprivileged process with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/19/2024
The vulnerability identified as CVE-2017-13323 resides within the String16 implementation in String16.cpp, representing a critical security flaw that can be exploited to achieve local privilege escalation. This issue stems from an integer overflow condition that occurs during string processing operations, specifically affecting the handling of string length calculations and memory allocation. The vulnerability manifests when an unprivileged process attempts to manipulate string data structures, creating conditions where integer arithmetic produces values that exceed the maximum representable range for the data type used in the calculation.
The technical flaw constitutes an integer overflow that leads to an out-of-bounds write condition, which is classified under CWE-190 as an integer overflow or wraparound. This vulnerability operates at the intersection of memory management and arithmetic operations, where the system fails to properly validate the results of integer calculations before using them as array indices or memory allocation parameters. The overflow occurs during the processing of string data structures, where the length calculation produces a value that, when used for memory allocation or indexing, exceeds the bounds of the allocated memory region, potentially allowing malicious data to overwrite adjacent memory locations.
The operational impact of this vulnerability extends to local privilege escalation scenarios where an unprivileged user can leverage the flaw to gain elevated system privileges without requiring any additional execution privileges or user interaction. This makes the vulnerability particularly dangerous as it can be exploited silently without detection, allowing attackers to execute arbitrary code with higher privileges than originally granted to the compromised process. The absence of user interaction requirements means that automated exploitation is possible, making this vulnerability suitable for both targeted attacks and broader exploitation campaigns.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1068 which involves local privilege escalation through exploitation of software vulnerabilities. The flaw represents a classic example of how memory safety issues in system libraries can be leveraged for privilege escalation, as the integer overflow directly impacts the memory layout and can potentially overwrite critical control structures or function pointers. The vulnerability's exploitation requires no user interaction, which means it can be triggered automatically by malicious code or through automated attack frameworks, making it particularly dangerous in environments where unprivileged processes are common.
Mitigation strategies for CVE-2017-13323 should focus on implementing proper integer overflow detection and bounds checking mechanisms within string processing functions. The recommended approach includes validating all integer calculations before use, particularly when these values are used for memory allocation or array indexing operations. Security patches should address the root cause by ensuring that string length calculations properly handle edge cases and prevent overflow conditions that could lead to memory corruption. Additionally, implementing robust memory protection mechanisms such as stack canaries, address space layout randomization, and heap metadata validation can provide defense-in-depth protection against exploitation attempts. The fix should also incorporate comprehensive input validation for string operations to prevent malicious inputs from triggering the overflow condition.