Platform
php
Component
php
Fixed in
7.3.16
7.4.4
CVE-2020-7065 describes a stack buffer overflow vulnerability within the mb_strtolower() function in PHP when using UTF-32LE encoding. This flaw can be triggered by specific invalid strings, leading to memory corruption, crashes, and potentially arbitrary code execution. This issue affects PHP versions 7.3.0 through 7.3.15 and 7.4.0 through 7.4.3. The vulnerability is resolved in PHP version 7.4.4.
CVE-2020-7065 affects PHP applications utilizing the mbstrtolower() function with UTF-32LE encoding. The vulnerability arises when specifically crafted, invalid UTF-32LE strings are passed to this function. This can trigger a stack-allocated buffer overflow, allowing an attacker to overwrite memory regions adjacent to the function's stack frame. A successful exploit could lead to a denial-of-service (DoS) condition through application crashes. More critically, memory corruption could potentially be leveraged to achieve arbitrary code execution (RCE). The blast radius is directly tied to the application's privileges. If the PHP application runs with elevated permissions (e.g., web server user), an attacker could potentially gain control of the underlying server. Data at risk includes sensitive information processed by the application, configuration files, and potentially system-level data if RCE is achieved. The specific impact depends on the application's functionality and the attacker's ability to craft a malicious UTF-32LE string that triggers the overflow and allows for code injection or memory manipulation. This vulnerability is particularly concerning for applications handling user-supplied data that is processed using mbstrtolower() with UTF-32LE encoding.
As of the current assessment, there are no publicly available exploitation reports or proof-of-concept (POC) code for CVE-2020-7065. This does not diminish the severity of the vulnerability, as the lack of public exploits does not guarantee that it cannot be exploited. The vulnerability's complexity, requiring specific UTF-32LE string crafting, may be a barrier to immediate exploitation. However, the potential for RCE warrants prompt attention and remediation. The absence of public exploits suggests a lower immediate urgency compared to vulnerabilities with readily available exploits, but proactive patching is still strongly recommended to prevent potential future exploitation. Security researchers are actively monitoring the vulnerability, and the exploitation landscape could change rapidly. Continuous monitoring of security advisories and threat intelligence feeds is crucial.
Exploit Status
EPSS
5.02% (90% percentile)
CVSS Vector
The primary mitigation for CVE-2020-7065 is to upgrade to a patched version of PHP. Affected versions include PHP 7.3.x prior to 7.3.16 and 7.4.x prior to 7.4.4. Upgrade to PHP 7.4.4 or later to resolve this vulnerability. If upgrading is not immediately feasible, a temporary workaround involves avoiding the use of mb_strtolower() with UTF-32LE encoding. This could involve using a different encoding or employing alternative string manipulation functions that do not exhibit this vulnerability. Thoroughly test any workarounds to ensure they do not introduce new issues or negatively impact application functionality. After applying the patch or implementing a workaround, verify the fix by testing the application with various UTF-32LE strings, including potentially malicious or invalid inputs, to confirm that the buffer overflow is no longer triggered. Consult the PHP security advisory for detailed upgrade instructions and any specific considerations for your environment.
Update to PHP version 7.3.16 or higher, or to version 7.4.4 or higher. This will correct the buffer overflow vulnerability in the mb_strtolower function with UTF-32LE encoding.
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CVE-2020-7065 is a vulnerability in PHP where the mb_strtolower() function, when used with UTF-32LE encoding and certain invalid strings, can lead to a stack buffer overflow.
You are affected if you are running PHP versions 7.3.x below 7.3.16 or 7.4.x below 7.4.4.
Upgrade to PHP 7.4.4 or later to resolve this vulnerability.
Currently, there are no publicly available exploitation reports or proof-of-concept code for CVE-2020-7065.
Refer to the National Vulnerability Database (NVD) entry at https://nvd.nist.gov/vuln/detail/CVE-2020-7065 and the PHP security advisory for more information.
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