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

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.