CVE-2018-4039 in Word Processor
Summary
by MITRE
An exploitable out-of-bounds write vulnerability exists in the PNG implementation of Atlantis Word Processor, version 3.2.7.2. This can allow an attacker to corrupt memory, which can result in code execution under the context of the application. An attacker must convince a victim to open a specially crafted document in order to trigger this vulnerability.
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Analysis
by VulDB Data Team • 06/12/2023
The vulnerability identified as CVE-2018-4039 represents a critical out-of-bounds write flaw within the Portable Network Graphics PNG implementation of Atlantis Word Processor version 3.2.7.2. This type of vulnerability falls under the CWE-787 category of out-of-bounds write conditions, where an application writes data beyond the boundaries of allocated memory buffers. The flaw specifically manifests when processing maliciously crafted PNG images embedded within document files, creating a potential pathway for remote code execution attacks. The vulnerability's exploitation requires social engineering to convince victims to open compromised documents, making it particularly dangerous in targeted attack scenarios.
The technical implementation of this vulnerability stems from inadequate input validation and boundary checking within the PNG parsing component of the word processor. When the application encounters a specially crafted PNG image, the parsing logic fails to properly validate the image dimensions or pixel data structure, leading to memory corruption when attempting to write beyond allocated buffer boundaries. This memory corruption can overwrite adjacent memory locations including function pointers, return addresses, or other critical application data structures. The vulnerability's impact is amplified by the fact that PNG format is commonly used in office documents, making it a prevalent attack vector for delivering malicious payloads.
From an operational perspective, this vulnerability creates significant risk for users who frequently handle documents containing embedded images or graphics. The attack scenario typically involves an attacker crafting a document with a malicious PNG image that appears legitimate to the end user. When the victim opens the document, the Atlantis Word Processor processes the PNG image, triggering the out-of-bounds write condition that can be leveraged to execute arbitrary code. The code execution occurs within the application context, potentially allowing attackers to gain full control over the victim's system, escalate privileges, or establish persistent access. This vulnerability particularly affects environments where users regularly open documents from untrusted sources or where document sharing occurs across organizational boundaries.
Mitigation strategies for CVE-2018-4039 should focus on both immediate remediation and long-term defensive measures. The primary recommendation involves updating to the latest version of Atlantis Word Processor where the vulnerability has been patched, as this addresses the core parsing logic flaw. Organizations should implement strict document validation policies that scan for potentially malicious embedded content and restrict the use of external image formats within sensitive environments. Network-level defenses can include content filtering solutions that block suspicious document types or images, while endpoint protection measures should monitor for abnormal application behavior during image processing. Additionally, user education programs should emphasize the importance of verifying document sources and avoiding opening attachments from unknown senders. The vulnerability demonstrates the importance of input validation and proper memory management in office productivity software, aligning with ATT&CK technique T1204.002 for legitimate credentials and T1059.001 for command and scripting interpreter usage in post-exploitation phases.