Executive Summary

CVE-2019-25477 is a buffer overflow vulnerability in RAR Password Recovery version 1.80 and earlier. It occurs when a local attacker inputs an oversized payload—exceeding 6000 bytes—into the User Name and Registration Code fields of the registration dialog.

This crafted input causes the application to crash due to improper handling of the large input size, resulting in a denial of service condition.

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Impact Analysis

This vulnerability can be exploited by a local attacker to crash the RAR Password Recovery application, causing a denial of service.

The impact is limited to availability, as the application becomes unusable after the crash triggered by the oversized input.

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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 attempting to reproduce the crash condition locally on the system running RAR Password Recovery 1.80 or earlier. Specifically, detection involves creating a payload exceeding 6000 bytes and pasting it into the User Name and Registration Code fields in the registration dialog to see if the application crashes.'}, {'type': 'paragraph', 'content': "A practical detection method is to generate a file containing 6000 'A' characters, copy its contents to the clipboard, and then paste it into the registration fields of the application to observe if it crashes."}, {'type': 'list_item', 'content': 'Create a file named "Evil.txt" with 6000 \'A\' characters (e.g., using a Python script or command line).'}, {'type': 'list_item', 'content': 'Copy the contents of "Evil.txt" to the clipboard.'}, {'type': 'list_item', 'content': 'Launch RAR Password Recovery and open the "Register" dialog.'}, {'type': 'list_item', 'content': 'Paste the copied payload into both the "User Name" and "Registration Code" fields.'}, {'type': 'list_item', 'content': 'Click "OK" and observe if the application crashes, indicating the presence of the vulnerability.'}, {'type': 'paragraph', 'content': 'Example command to create the payload file on Windows using PowerShell: `powershell -Command "\'A\' * 6000 | Out-File Evil.txt -Encoding ascii"`'}] [2]

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Mitigation Strategies

Immediate mitigation steps include avoiding the use of the registration dialog fields for inputting large or untrusted data, as the vulnerability is triggered by oversized payloads in these fields.

Since the vulnerability requires local access and user interaction to paste the malicious input, restricting access to the application and educating users to not paste suspicious or large inputs into the registration fields can reduce risk.

If possible, update to a newer version of RAR Password Recovery where this vulnerability is fixed or consider using alternative software that does not have this issue.

As a temporary workaround, avoid using the registration dialog or disable the registration feature if feasible.

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