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.
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.
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.
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.
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.