Executive Summary

[{'type': 'paragraph', 'content': "CVE-2026-27749 is a high-severity vulnerability in Avira Internet Security's System Speedup component. The issue arises because the Avira.SystemSpeedup.RealTimeOptimizer.exe process, which runs with SYSTEM privileges, deserializes data from a file in C:\\ProgramData using the .NET BinaryFormatter without validating the input or using deserialization safeguards."}, {'type': 'paragraph', 'content': 'Since the file can be created or modified by a local user under default settings, an attacker can supply a specially crafted serialized payload. When this payload is deserialized by the privileged process, it can lead to arbitrary code execution with SYSTEM-level privileges.'}] [1]

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Impact Analysis

This vulnerability allows a local attacker to escalate their privileges to SYSTEM level by exploiting insecure deserialization in a highly privileged process. This means an attacker with limited access could execute arbitrary code with the highest system privileges, potentially taking full control of the affected system.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': 'Detection of this vulnerability involves checking for the presence and version of the Avira Internet Security System Speedup component, specifically the Avira.SystemSpeedup.RealTimeOptimizer.exe process running with SYSTEM privileges.'}, {'type': 'paragraph', 'content': 'You can verify if the vulnerable executable is running by using system process listing commands.'}, {'type': 'list_item', 'content': 'On Windows, use: tasklist /FI "IMAGENAME eq Avira.SystemSpeedup.RealTimeOptimizer.exe"'}, {'type': 'list_item', 'content': 'Check the file in C:\\ProgramData that the process deserializes from, to see if it has been modified or created by an untrusted user.'}, {'type': 'paragraph', 'content': 'Since the vulnerability involves deserialization of untrusted data from a file, monitoring file changes in C:\\ProgramData related to Avira System Speedup may help detect exploitation attempts.'}] [1]

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Mitigation Strategies

Immediate mitigation steps include restricting write permissions to the file in C:\ProgramData that is deserialized by Avira.SystemSpeedup.RealTimeOptimizer.exe to prevent untrusted users from modifying or creating the file.

Additionally, ensure that the Avira Internet Security System Speedup component is updated to a version that addresses this vulnerability, if available.

As a temporary measure, consider stopping or disabling the Avira.SystemSpeedup.RealTimeOptimizer.exe process if it is not critical to your system operations.

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