Avira Internet Security contains a time-of-check time-of-use (TOCTOU) vulnerability in the Optimizer component. A privileged service running as SYSTEM identifies directories for cleanup during a scan phase and subsequently deletes them during a separate cleanup phase without revalidating the target path. A local attacker can replace a previously scanned directory with a junction or reparse point before deletion occurs, causing the privileged process to delete an unintended system location. This may result in deletion of protected files or directories and can lead to local privilege escalation, denial of service, or system integrity compromise depending on the affected target.

Avira Internet Security contains a deserialization of untrusted data vulnerability in the System Speedup component. The Avira.SystemSpeedup.RealTimeOptimizer.exe process, which runs with SYSTEM privileges, deserializes data from a file located in C:\\ProgramData using .NET BinaryFormatter without implementing input validation or deserialization safeguards. Because the file can be created or modified by a local user in default configurations, an attacker can supply a crafted serialized payload that is deserialized by the privileged process, resulting in arbitrary code execution as SYSTEM.

Avira Internet Security contains an improper link resolution vulnerability in the Software Updater component. During the update process, a privileged service running as SYSTEM deletes a file under C:\\ProgramData without validating whether the path resolves through a symbolic link or reparse point. A local attacker can create a malicious link to redirect the delete operation to an arbitrary file, resulting in deletion of attacker-chosen files with SYSTEM privileges. This may lead to local privilege escalation, denial of service, or system integrity compromise depending on the targeted file and operating system configuration.

Avira Prime Link Following Local Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Avira Prime. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the Avira Spotlight Service. By creating a symbolic link, an attacker can abuse the service to delete a file. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-21600.

An issue was discovered in Avira Phantom VPN through 2.23.1 for macOS. The VPN client insecurely configures the operating system such that all IP traffic to the VPN server's IP address is sent in plaintext outside the VPN tunnel, even if this traffic is not generated by the VPN client, while simultaneously using plaintext DNS to look up the VPN server's IP address. This allows an adversary to trick the victim into sending traffic to arbitrary IP addresses in plaintext outside the VPN tunnel. NOTE: the tunnelcrack.mathyvanhoef.com website uses this CVE ID to refer more generally to "ServerIP attack, combined with DNS spoofing, that can leak traffic to an arbitrary IP address" rather than to only Avira Phantom VPN.

A vulnerability within the Avira network protection feature allowed an attacker with local execution rights to cause an overflow. This could corrupt the data on the heap and lead to a denial-of-service situation. Issue was fixed with Endpointprotection.exe version 1.0.2303.633

Avira Security for Windows contains an unquoted service path which allows attackers with local administrative privileges to cause a Denial of Service. The issue was fixed with Avira Security version 1.1.78

Norton, Avira, Avast and AVG Antivirus for Windows may be susceptible to a Privilege Escalation vulnerability, which is a type of issue whereby an attacker may attempt to compromise the software application to gain elevated access to resources that are normally protected from an application or user.

A vulnerability within the Software Updater functionality of Avira Security for Windows allowed an attacker with write access to the filesystem, to escalate his privileges in certain scenarios. The issue was fixed with Avira Security version 1.1.72.30556.

A vulnerability within the Avira Password Manager Browser Extensions provided a potential loophole where, if a user visited a page crafted by an attacker, the discovered vulnerability could trigger the Password Manager Extension to fill in the password field automatically. An attacker could then access this information via JavaScript. The issue was fixed with the browser extensions version 2.18.5 for Chrome, MS Edge, Opera, Firefox, and Safari.

Avira Free Antivirus through 15.0.2005.1866 allows local users to discover user credentials. The functions of the executable file Avira.PWM.NativeMessaging.exe are aimed at collecting credentials stored in Chrome, Firefox, Opera, and Edge. The executable does not verify the calling program and thus a request such as fetchChromePasswords or fetchCredentials will succeed. NOTE: some third parties have stated that this is "not a vulnerability.

An elevation of privilege vulnerability exists in Avira Software Updater before 2.0.6.27476 due to improperly handling file hard links. This allows local users to obtain take control of arbitrary files.

Avira Antivirus before 5.0.2003.1821 on Windows allows privilege escalation or a denial of service via abuse of a symlink.

An issue was discovered in Avira Free-Antivirus before 15.0.2004.1825. The Self-Protection feature does not prohibit a write operation from an external process. Thus, code injection can be used to turn off this feature. After that, one can construct an event that will modify a file at a specific location, and pass this event to the driver, thereby defeating the anti-virus functionality.

Avira AV Engine before 8.3.54.138 allows virus-detection bypass via a crafted ISO archive. This affects versions before 8.3.54.138 of Antivirus for Endpoint, Antivirus for Small Business, Exchange Security (Gateway), Internet Security Suite for Windows, Prime, Free Security Suite for Windows, and Cross Platform Anti-malware SDK. NOTE: Vendor asserts that vulnerability does not exist in product

A Denial of Service (infinite loop) vulnerability exists in Avira AntiVir Engine before 8.2.12.58 via an unspecified function in the PDF Scanner Engine.

Avira Free Antivirus 15.0.1907.1514 is prone to a local privilege escalation through the execution of kernel code from a restricted user.

Avira Software Updater before 2.0.6.21094 allows a DLL side-loading attack. NOTE: The vendor thinks that this vulnerability is invalid because exploiting it would require at least administrator privileges and would gain only SYSTEM privileges

An issue was discovered in Avira Free Security Suite 10. The permissive access rights on the SoftwareUpdater folder (files / folders and configuration) are incompatible with the privileged file manipulation performed by the product. Files can be created that can be used by an unprivileged user to obtain SYSTEM privileges. Arbitrary file creation can be achieved by abusing the SwuConfig.json file creation: an unprivileged user can replace these files by pseudo-symbolic links to arbitrary files. When an update occurs, a privileged service creates a file and sets its access rights, offering write access to the Everyone group in any directory.

Avira Antivirus engine versions before 8.3.36.60 allow remote code execution as NT AUTHORITY\SYSTEM via a section header with a very large relative virtual address in a PE file, causing an integer overflow and heap-based buffer underflow.

The Avira Mobile Security app before 1.5.11 for iOS sends sensitive login information in cleartext.

Code injection vulnerability in Avira Total Security Suite 15.0 (and earlier), Optimization Suite 15.0 (and earlier), Internet Security Suite 15.0 (and earlier), and Free Security Suite 15.0 (and earlier) allows a local attacker to bypass a self-protection mechanism, inject arbitrary code, and take full control of any Avira process via a "DoubleAgent" attack. One perspective on this issue is that (1) these products do not use the Protected Processes feature, and therefore an attacker can enter an arbitrary Application Verifier Provider DLL under Image File Execution Options in the registry; (2) the self-protection mechanism is intended to block all local processes (regardless of privileges) from modifying Image File Execution Options for these products; and (3) this mechanism can be bypassed by an attacker who temporarily renames Image File Execution Options during the attack.

Use-after-free vulnerability in the Update Manager service in Avira Management Console allows remote attackers to execute arbitrary code via a large header.

The Avira Secure Backup (aka com.avira.avirabackup) application 1.2.3 for Android does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

Race condition in Avira Premium Security Suite 10.0.0.536 on Windows XP allows local users to bypass kernel-mode hook handlers, and execute dangerous code that would otherwise be blocked by a handler but not blocked by signature-based malware detection, via certain user-space memory changes during hook-handler execution, aka an argument-switch attack or a KHOBE attack. NOTE: this issue is disputed by some third parties because it is a flaw in a protection mechanism for situations where a crafted program has already begun to execute