A significant new vulnerability has been identified in certain HP LaserJet printer models, specifically those in the HP LaserJet Pro, HP Enterprise LaserJet, and HP LaserJet Managed Printers categories. This vulnerability has been assigned the identifier CVE-2024-0794 and concerns itself with the rendering of fonts embedded within PDF files. In essence, when a vulnerable printer handles a PDF file with embedded fonts, it may be possible for an attacker to execute arbitrary code on the printer. This post will detail the technical specifics of the vulnerability, discuss potential exploit scenarios, and enumerate the affected printer models.

Vulnerability Details

The heart of CVE-2024-0794 is a buffer overflow vulnerability that arises when vulnerable printers render fonts that have been embedded in a PDF file. It appears that the specific code that deals with font rendering mishandles the input, leading to a buffer overflow.

The following code snippet demonstrates a high-level overview of the rendering process that is vulnerable to a buffer overflow attack:

void renderFont(FontObject *fontObj) {
    char fontDataBuffer[1024];
    ...
    for (int i = ; i < fontObj->numGlyphs; ++i) {
        memcpy(fontDataBuffer + i * GLYPH_SIZE, fontObj->glyphData[i], fontObj->glyphDataSize);
        ...
    }
}

In this example, the memcpy function is used to copy the data associated with each glyph from the input PDF file into a fixed-size buffer (fontDataBuffer). However, there is no proper boundary check to ensure that the buffer doesn't overflow.

By crafting a specific PDF file with embedded fonts and exploiting the buffer overflow in certain HP LaserJet printer models, an attacker could potentially overwrite the memory of the printer and execute arbitrary code remotely.

Affected Models

A list of potentially vulnerable printers can be found in the official HP Security Bulletin[^1^]. Some of the affected models include, but are not limited to:

HP LaserJet Managed E65150dn

For a comprehensive list, please refer to the HP Security Bulletin.

Exploit Scenario

In a likely exploit scenario, an attacker could send a specifically crafted PDF file to a vulnerable HP LaserJet printer either via email, if the printer is configured to receive email attachments, or through a direct printer connection. Once the malicious PDF file is received and processed by the printer, the attacker could gain control of the printer by executing arbitrary code remotely.

Unauthorized access to sensitive documents being printed

- Printer hijacking, potentially using the printer to launch attacks on other devices within the same network

Remediation

To protect against CVE-2024-0794, it is crucial for those using potentially affected printers to apply all relevant firmware updates as advised by the manufacturer. Please consult the official HP Security Bulletin[^1^] for more information regarding specific printer models and the associated firmware updates.

In addition to firmware updates, it is also important to follow basic security best practices, such as:

Educating users about potential attack vectors and the significance of printer security

More details about the CVE-2024-0794 vulnerability can be found on the official CVE website[^2^].

References

[^1^]: HP Security Bulletin
[^2^]: CVE Details

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_Disclaimer: This post is provided for informational purposes only and should not be used as a substitute for professional security advice. Users should consult with the respective printer manufacturer for specific updates and remedies._

Timeline

Published on: 02/20/2024 18:15:50 UTC
Last modified on: 02/21/2024 01:15:07 UTC