Vulnerabilities

Integer Overflow or Wraparound vulnerability in Avast Antivirus (25.1.981.6) on Windows allows Privilege Escalation.This issue affects Antivirus: from 25.1.981.6 before 25.3.

Double fetch in sandbox kernel driver in Avast/AVG Antivirus <25.3 on windows allows local attacker to escalate privelages via pool overflow.

Avast Free Antivirus AvastSvc Link Following Local Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Avast Free Antivirus. 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 Avast Service. By creating a symbolic link, an attacker can abuse the service to delete a folder. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-23731.

Avast Cleanup Premium Link Following Local Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Avast Cleanup Premium. 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 Avast Cleanup 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-22894.

An null-pointer-derefrence in the engine module in AVG/Avast Antivirus signature <24092400 released on 24/Sep/2024 on MacOS allows a malformed xar file to crash the application during file processing.

A sym-linked file accessed via the repair function in Avast Antivirus troubleshooting -> repair) feature, which attempts to delete a file in the current user's AppData directory as NT AUTHORITY\SYSTEM. A low-privileged user can make a pseudo-symlink and a junction folder and point to a file on the system. This can provide a low-privileged user an Elevation of Privilege to win a race-condition which will re-create the system files and make Windows callback to a specially-crafted file which could be used to launch a privileged shell instance. This issue affects Avast Antivirus prior to 24.2.

Avast Premium Security Sandbox Protection Link Following Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Avast Premium Security. 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 implementation of the sandbox feature. By creating a symbolic link, an attacker can abuse the service to create arbitrary namespace objects. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. . Was ZDI-CAN-20383.

A time-of-check to time-of-use (TOCTOU) bug in handling of IOCTL (input/output control) requests. This TOCTOU bug leads to an out-of-bounds write vulnerability which can be further exploited, allowing an attacker to gain full local privilege escalation on the system.This issue affects Avast/Avg Antivirus: 23.8.

Buffer Overflow vulnerability in Avast AntiVirus before v.19.7 allows a local attacker to cause a denial of service via a crafted request to the aswSnx.sys driver.

Avast and AVG Antivirus for Windows were susceptible to a Time-of-check/Time-of-use (TOCTOU) vulnerability in the Quarantine process, leading to arbitrary file/directory deletion. The issue was fixed with Avast and AVG Antivirus version 22.11 and virus definitions from 14 February 2023 or later.

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.

The aswjsflt.dll library from Avast Antivirus windows contained a potentially exploitable heap corruption vulnerability that could enable an attacker to bypass the sandbox of the application it was loaded into, if applicable. This issue was fixed in version 18.0.1478 of the Script Shield Component.

A vulnerability within the malware removal functionality of Avast and AVG Antivirus allowed an attacker with write access to the filesystem, to escalate his privileges in certain scenarios. The issue was fixed with Avast and AVG Antivirus version 22.10.

An arbitrary file write vulnerability in Avast Premium Security before v21.11.2500 (build 21.11.6809.528) allows attackers to cause a Denial of Service (DoS) via a crafted DLL file.

Privilege escalation vulnerability in the Sandbox component of Avast Antivirus prior to 20.4 allows a local sandboxed code to gain elevated privileges by using system IPC interfaces which could lead to exit the sandbox and acquire SYSTEM privileges.

An issue was discovered in retdec v3.3. In function canSplitFunctionOn() of ir_modifications.cpp, there is a possible out of bounds read due to a heap buffer overflow. The impact is: Deny of Service, Memory Disclosure, and Possible Code Execution.

This vulnerability allows local attackers to delete arbitrary directories on affected installations of Avast Premium Security 20.8.2429 (Build 20.8.5653.561). 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 AvastSvc.exe module. By creating a directory junction, an attacker can abuse the service to delete a directory. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-12082.

The VPN service in AVAST SecureLine before 5.6.4982.470 allows local users to write to arbitrary files via an Object Manager symbolic link from the log directory (which has weak permissions).

An issue was discovered in the Login Password feature of the Password Manager component in Avast Antivirus 20.1.5069.562. An entered password continues to be stored in Windows main memory after a logout, and after a Lock Vault operation.

An elevation of privilege vulnerability exists in Avast Free Antivirus and AVG AntiVirus Free before 20.4 due to improperly handling hard links. The vulnerability allows local users to take control of arbitrary files.

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 bypass intended access restrictions on tasks from an untrusted process, when Self Defense is enabled.

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.)

The Avast AV parsing engine allows virus-detection bypass via a crafted ZIP archive. This affects versions before 12 definitions 200114-0 of Antivirus Pro, Antivirus Pro Plus, and Antivirus for Linux.

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.

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.

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.