Avas!t

An issue was discovered in Avast Antivirus before 20. The aswTask RPC endpoint for the TaskEx library in the Avast Service (AvastSvc.exe) allows attackers to trigger a shutdown via RPC from a Low Integrity process via TempShutDownMachine.Show less

An issue was discovered in Avast Antivirus before 20. The aswTask RPC endpoint for the TaskEx library in the Avast Service (AvastSvc.exe) allows attackers to achieve Arbitrary File Deletion from Avast Program Path via RPC, when Self Defense is Enabled.Show less

Avast AntiTrack before 1.5.1.172 and AVG Antitrack before 2.0.0.178 proxies traffic to HTTPS sites but does not validate certificates, and thus a man-in-the-middle can host a malicious website using a self-signed certificate. No special action necessary by the victim using AntiTrack with "Allow filtering of HTTPS traffic for tracking detection" enabled. (This is the default configuration.)Show less

A Local Privilege Escalation issue was discovered in Avast Secure Browser 76.0.1659.101. The vulnerability is due to an insecure ACL set by the AvastBrowserUpdate.exe (which is running as NT AUTHORITY\SYSTEM) when AvastSecureBrowser.exe checks for new updates. When the update check is triggered, the elevated process cleans the ACL of the Update.ini file in %PROGRAMDATA%\Avast Software\Browser\Update\ and sets all privileges to group Everyone. Because any low-privileged user can create, delete, or modify the Update.ini file stored in this location, an attacker with low privileges can create a hard link named Update.ini in this folder, and make it point to a file writable by NT AUTHORITY\SYSTEM. Once AvastBrowserUpdate.exe is triggered by the update check functionality, the DACL is set to a misconfigured value on the crafted Update.ini and, consequently, to the target file that was previously not writable by the low-privileged attacker.Show less

In Avast Premium Security 19.8.2393, attackers can send a specially crafted request to the local web server run by Avast Antivirus on port 27275 to support Bank Mode functionality. A flaw in the processing of a command allows execution of arbitrary OS commands with the privileges of the currently logged in user. This allows for example attackers who compromised a browser extension to escape from the browser sandbox.Show less

XSS in the Video Downloader component before 1.5 of Avast Secure Browser 77.1.1831.91 and AVG Secure Browser 77.0.1790.77 allows websites to execute their code in the context of this component. While Video Downloader is technically a browser extension, it is granted a very wide set of privileges and can for example access cookies and browsing history, spy on the user while they are surfing the web, and alter their surfing experience in almost arbitrary ways.Show less

A Cross Site Scripting (XSS) issue exists in Avast AntiVirus (Free, Internet Security, and Premiere Edition) 19.3.2369 build 19.3.4241.440 in the Network Notification Popup, allowing an attacker to execute JavaScript code via an SSID Name.Show less

An issue was discovered in Avast antivirus before 19.8 and AVG antivirus before 19.8. A DLL Preloading vulnerability allows an attacker to implant %WINDIR%\system32\wbemcomn.dll, which is loaded into a protected-light process (PPL) and might bypass some of the self-defense mechanisms. This affects all components that use WMI, e.g., AVGSvc.exe 19.6.4546.0 and TuneupSmartScan.dll 19.1.884.0.Show less

In Avast Antivirus before 19.4, a local administrator can trick the product into renaming arbitrary files by replacing the Logs\Update.log file with a symlink. The next time the product attempts to write to the log file, the target of the symlink is renamed. This defect can be exploited to rename a critical product file (e.g., AvastSvc.exe), causing the product to fail to start on the next system restart.Show less

In Avast Antivirus before v17, an unprivileged user (and thus malware or a virus) can mark an arbitrary process as Trusted from the perspective of the Avast product. This bypasses the Self-Defense feature of the product, opening a door to subsequent attack on many of its components.Show less

In Avast Antivirus before v17, using the LPC interface API exposed by the AvastSVC.exe Windows service, it is possible to launch predefined binaries, or replace or delete arbitrary files. This vulnerability is exploitable by any unprivileged user when Avast Self-Defense is disabled. It is also exploitable in conjunction with CVE-2017-8308 when Avast Self-Defense is enabled. The vulnerability allows for Denial of Service attacks and hiding traces of a possible attack.Show less

Code injection vulnerability in Avast Premier 12.3 (and earlier), Internet Security 12.3 (and earlier), Pro Antivirus 12.3 (and earlier), and Free Antivirus 12.3 (and earlier) allows a local attacker to bypass a self-protection mechanism, inject arbitrary code, and take full control of any Avast 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.Show less

Avast Internet Security v11.x.x, Pro Antivirus v11.x.x, Premier v11.x.x, Free Antivirus v11.x.x, Business Security v11.x.x, Endpoint Protection v8.x.x, Endpoint Protection Plus v8.x.x, Endpoint Protection Suite v8.x.x, Endpoint Protection Suite Plus v8.x.x, File Server Security v8.x.x, and Email Server Security v8.x.x allow attackers to bypass the DeepScreen feature via a DeviceIoControl call.Show less

Heap-based buffer overflow in the Avast virtualization driver (aswSnx.sys) in Avast Internet Security, Pro Antivirus, Premier, and Free Antivirus before 11.1.2253 allows local users to gain privileges via a Unicode file path in an IOCTL request.Show less