AvastCVEs & Vulnerabilities

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.

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.

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.

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.

Avast Free Antivirus prior to 19.1.2360 stores user credentials in memory upon login, which allows local users to obtain sensitive information by dumping AvastUI.exe application memory and parsing the data.

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.

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.

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.

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.

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.

Avast allows remote attackers to cause a denial of service (memory corruption) and possibly execute arbitrary code via a crafted PE file, related to authenticode parsing.

Directory traversal vulnerability in Avast before 150918-0 allows remote attackers to delete or write to arbitrary files via a crafted entry in a ZIP archive.

The avast! Mobile Security application before 2.0.4400 for Android allows attackers to cause a denial of service (application crash) via a crafted application that sends an intent to com.avast.android.mobilesecurity.app.scanner.DeleteFileActivity with zero arguments.

Untrusted search path vulnerability in avast! Free Antivirus version 5.0.594 and earlier allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse mfc90loc.dll that is located in the same folder as an avast license (.avastlic) file.

Aavmker4.sys in avast! 4.8 through 4.8.1368.0 and 5.0 before 5.0.418.0 running on Windows 2000 and XP does not properly validate input to IOCTL 0xb2d60030, which allows local users to cause a denial of service (system crash) or execute arbitrary code to gain privileges via IOCTL requests using crafted kernel addresses that trigger memory corruption.

Heap-based buffer overflow in aswRdr.sys (aka the TDI RDR driver) in avast! Home and Professional 4.8.1356.0 allows local users to cause a denial of service (memory corruption) or possibly gain privileges via crafted arguments to IOCTL 0x80002024.

Unspecified vulnerability in ashWsFtr.dll in avast! Home and Professional for Windows before 4.8.1356 has unknown impact and local attack vectors.

aavmKer4.sys in avast! Home and Professional for Windows before 4.8.1356 does not properly validate input to IOCTLs (1) 0xb2d6000c and (2) 0xb2d60034, which allows local users to gain privileges via IOCTL requests using crafted kernel addresses that trigger memory corruption, a different vulnerability than CVE-2008-1625.

Stack-based buffer overflow in aswMon2.sys in avast! Home and Professional for Windows 4.8.1351, and possibly other versions before 4.8.1356, allows local users to cause a denial of service (system crash) and possibly gain privileges via a crafted IOCTL request to IOCTL 0xb2c80018.

Multiple stack-based buffer overflows in avast! Linux Home Edition 1.0.5, 1.0.5-1, and 1.0.8 allow remote attackers to cause a denial of service (application crash) or execute arbitrary code via a malformed (1) ISO or (2) RPM file.

avast! antivirus 4.8.1281.0, when Internet Explorer 6 or 7 is used, allows remote attackers to bypass detection of malware in an HTML document by placing an MZ header (aka "EXE info") at the beginning, and modifying the filename to have (1) no extension, (2) a .txt extension, or (3) a .jpg extension, as demonstrated by a document containing a CVE-2006-5745 exploit.

aavmker4.sys in avast! Home and Professional 4.7 for Windows does not properly validate input to IOCTL 0xb2d60030, which allows local users to gain privileges via certain IOCTL requests.

Unspecified vulnerability in avast! 4 Home and Professional Editions before 4.7.1098 allows remote attackers to have an unknown impact via a crafted TAR archive.

Heap-based buffer overflow in the CAB unpacker in avast! Anti-Virus Managed Client before 4.7.700 allows user-assisted remote attackers to execute arbitrary code via a crafted CAB archive, resulting from an "integer cast around".

unzoo.c, as used in multiple products including AMaViS 2.4.1 and earlier, allows remote attackers to cause a denial of service (infinite loop) via a ZOO archive with a direntry structure that points to a previous file.

avast! antivirus before 4.7.981 allows remote attackers to cause a denial of service (infinite loop) via a ZOO archive with a direntry structure that points to a previous file.