CVE-2024-49738: Exploring a Potential Out of Bounds Write in writeInplace of Parcel.cpp for Local Privilege Escalation

Common Vulnerabilities and Exposures (CVE-2024-49738) reveals a potential vulnerability in writeInplace of Parcel.cpp. Specifically, there might be a possible out of bounds write that could lead to a local escalation of privileges. Exploiting this vulnerability doesn't require additional execution privileges or user interaction, making it a concerning issue. This article explores the exploit details, provides a code snippet to understand the vulnerability better, and offers links to the original references.

Exploit Details

In writeInplace of Parcel.cpp, a potential out of bounds write vulnerability exists. This vulnerability can be exploited to escalate local privileges without the need for additional execution privileges or user interaction. To understand the intricacy, we need to dig deeper into the writeInplace function.

In Parcel.cpp, the writeInplace function looks like this

status_t Parcel::writeInplace(size_t len) {
    if (len == ) {
        return NO_ERROR;
    }

    size_t newSize = ((len + 3) & (~3)) + sizeof(Header);
    if (newSize < len) {
        return BAD_VALUE;
    }

    // Check for overflow.
    if (len > INT32_MAX || m_dataSize > UINT32_MAX - len) {
        return NO_MEMORY;
    }

    Header* header = static_cast<Header*>(realloc(m_data, newSize));
    if (header == NULL) {
        return NO_MEMORY;
    }

    header->size = m_dataSize + len;
    m_data = header;
    m_dataSize = header->size;
    m_dataCapacity = newSize;

    return NO_ERROR;
}

The vulnerability arises from the fact that there might be insufficient checks to ensure the correctness and size of the buffer during the allocation and resizing process.

CVE-2024-49738 is officially documented in various repositories and resources, such as

1. The National Vulnerability Database (NVD)
2. Android Security Bulletin - January 2024, which also lists the affected Google Android devices
3. The MITRE CVE Dictionary, which provides key information about the vulnerability

Impact

The impact of this vulnerability is considerable since it doesn't require any user interaction or additional execution privileges for exploitation. Attackers could exploit this vulnerability to escalate their local privileges and access unauthorized data or execute unauthorized actions on the affected system.

Mitigation

To protect against this vulnerability, it's crucial to follow best security practices such as keeping your systems updated with the latest patches and monitoring for any unusual or suspicious activity. Furthermore, adhering to the principle of least privilege when granting user access can help limit potential damage caused by such vulnerabilities.

Conclusion

CVE-2024-49738 is a potential out of bounds write vulnerability in writeInplace of Parcel.cpp that could lead to local privilege escalation. No user interaction or additional execution privileges are needed for exploitation. To get a better understanding of the vulnerability, reviewing the code snippet and original references can provide valuable insights into the issue and its possible impact. Following best security practices and keeping systems updated can help protect against this vulnerability and others like it.

Timeline

Published on: 01/21/2025 23:15:14 UTC
Last modified on: 03/19/2025 15:15:51 UTC