Incomplete List of Disallowed Inputs (CWE-184) in the dangerous-extension confirmation of the archive object viewer (peach.pas, grid_obj_open) in PeaZip 10.5.0 through 11.2.0 on Windows allows an attacker who convinces a victim to open a…

Overview

Incomplete List of Disallowed Inputs (CWE-184) in the dangerous-extension confirmation of the archive object viewer (peach.pas, grid_obj_open) in PeaZip 10.5.0 through 11.2.0 on Windows allows an attacker who convinces a victim to open an entry of a crafted archive to execute a program, or an arbitrary command, with no confirmation dialog. The prompt (Do you want to run this file?) is gated by SECEXTCONST, a hard-coded list of seven extensions (exe cmd msi bat ps1 vbs reg); the check is an exact string comparison of the entry extension against that list, so it answers only whether the extension is one of the seven and never whether the shell will execute the file. Shell-executable and scripting-host types that Windows runs through ShellExecuteW are absent from the list, among them .url and .lnk. An archived Windows Internet Shortcut (.url) whose URL line is attacker-controlled is launched with no prompt, while the byte-identical content in an entry named .bat does raise the warning in the same session. A .lnk entry raises the ceiling from launching a program to running a command line, because a Windows shortcut carries arguments: a proof-of-concept shortcut targeting cmd.exe with an attacker-chosen command line executed with no prompt. The shortcut target is not confined to the local disk; the shell also resolved an attacker-named UNC path (fetching a remote payload was only attempted, not demonstrated). No privilege escalation; everything runs as the user who opened the archive.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.