Executive Summary

[{'type': 'paragraph', 'content': 'CVE-2019-25466 is a local structured exception handling (SEH) buffer overflow vulnerability in Easy File Sharing Web Server version 7.2. It occurs in the "New User" functionality where an attacker can create a malicious username containing a specially crafted payload. This payload includes 4059 bytes of padding followed by specific SEH overwrite values that trigger the overflow when adding a new user account.'}, {'type': 'paragraph', 'content': 'By exploiting this vulnerability, an attacker with local access can execute arbitrary code on the affected system. The exploit leverages a known vulnerable instruction sequence in the ImageLoad.dll module, which lacks modern exploit mitigations such as ASLR or SafeSEH.'}] [1, 2]

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Impact Analysis

This vulnerability allows a local attacker to execute arbitrary code on the affected system by exploiting a buffer overflow in the user account creation process. Successful exploitation can lead to full compromise of the system, including unauthorized access, data manipulation, and disruption of services.

• Execution of arbitrary code with potentially elevated privileges.
• Compromise of system confidentiality, integrity, and availability.
• Potential for further attacks or malware installation due to system control.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by monitoring attempts to add new user accounts with unusually long or malformed usernames, specifically those containing a payload of 4059 bytes followed by specific SEH overwrite values.'}, {'type': 'paragraph', 'content': "Since the exploit involves creating a malicious username that triggers a buffer overflow in the 'New User' functionality of Easy File Sharing Web Server 7.2, detection can focus on identifying such crafted usernames in logs or during user creation attempts."}, {'type': 'paragraph', 'content': 'No specific detection commands are provided in the resources, but you can use system or application logs to look for usernames with suspiciously long strings or unusual characters.'}, {'type': 'paragraph', 'content': 'For example, on Windows systems, you might use PowerShell or command line tools to search logs or user account creation events for usernames exceeding normal length or containing non-standard characters.'}] [1, 2]

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Mitigation Strategies

[{'type': 'paragraph', 'content': 'Immediate mitigation steps include restricting local access to the Easy File Sharing Web Server 7.2 to trusted users only, as the vulnerability requires local attacker access.'}, {'type': 'paragraph', 'content': 'Avoid allowing untrusted users to create new user accounts on the system, or implement input validation to prevent usernames with excessive length or malicious payloads.'}, {'type': 'paragraph', 'content': 'Since the vulnerable module (ImageLoad.dll) lacks modern exploit mitigations like ASLR and SafeSEH, consider applying any available patches or upgrading to a newer, secure version of the software if available.'}, {'type': 'paragraph', 'content': "If no patch is available, consider disabling the 'New User' functionality or restricting it until a fix can be applied."}] [1, 2]

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