peass-ng/PEASS-ng · error · ArgumentOutOfRangeException

Task names may not include any characters which are invalid

Error message

Task names may not include any characters which are invalid for file names.

What it means

Path-validation guard in RegisterTaskDefinition for Task Scheduler 1.0: the task path is tested against the set of characters invalid in file names (via Path.GetInvalidFileNameChars) because V1 stores each task as a .job file whose name is the task path. Any invalid filename character (e.g. \<>:*?"| or control chars) in path triggers this ArgumentOutOfRangeException.

Source

Thrown at winPEAS/winPEASexe/winPEAS/TaskScheduler/TaskFolder.cs:519

				{
					throw new ArgumentException("A password must be supplied when specifying TaskLogonType.Password or TaskLogonType.InteractiveTokenOrPassword or TaskLogonType.S4U from another account.", nameof(password));
				}*/
                else if (logonType == TaskLogonType.Group && password != null)
                {
                    throw new ArgumentException(@"A password cannot be supplied when specifying TaskLogonType.Group.", nameof(password));
                }
                // The following line compensates for an omission in the native library that never actually sets the registration date (thanks ixm7).
                if (definition.RegistrationInfo.Date == DateTime.MinValue) definition.RegistrationInfo.Date = DateTime.Now;
                var iRegTask = v2Folder.RegisterTaskDefinition(path, definition.v2Def, (int)createType, userId ?? user.Name, password, logonType, sddl);
                if (createType == TaskCreation.ValidateOnly && iRegTask == null)
                    return null;
                return Task.CreateTask(TaskService, iRegTask);
            }

            // Check for V1 invalid task names
            string invChars = Regex.Escape(new string(System.IO.Path.GetInvalidFileNameChars()));
            if (Regex.IsMatch(path, @"[" + invChars + @"]"))
                throw new ArgumentOutOfRangeException(nameof(path), @"Task names may not include any characters which are invalid for file names.");
            if (Regex.IsMatch(path, @"\.[^" + invChars + @"]{0,3}\z"))
                throw new ArgumentOutOfRangeException(nameof(path), @"Task names ending with a period followed by three or fewer characters cannot be retrieved due to a bug in the native library.");

            // Adds ability to set a password for a V1 task. Provided by Arcao.
            TaskFlags flags = definition.v1Task.GetFlags();
            if (logonType == TaskLogonType.InteractiveTokenOrPassword && string.IsNullOrEmpty(password))
                logonType = TaskLogonType.InteractiveToken;
            switch (logonType)
            {
                case TaskLogonType.Group:
                case TaskLogonType.S4U:
                case TaskLogonType.None:
                    throw new NotV1SupportedException("This LogonType is not supported on Task Scheduler 1.0.");
                case TaskLogonType.InteractiveToken:
                    flags |= (TaskFlags.RunOnlyIfLoggedOn | TaskFlags.Interactive);
                    definition.v1Task.SetAccountInformation(user.Name, IntPtr.Zero);
                    break;
                case TaskLogonType.ServiceAccount:

View on GitHub (pinned to 53fb989abc)

Solutions

1. Sanitize the task path by removing or replacing characters returned by System.IO.Path.GetInvalidFileNameChars() before registering
2. Use only alphanumerics, dashes and underscores in the task name

When it happens

Trigger: Thrown at winPEAS/winPEASexe/winPEAS/TaskScheduler/TaskFolder.cs:519 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/689db0b0ec546763. Report an issue: GitHub.