fix(security): handle PowerShell EncodedCommand abbreviations (#270)

Handles PowerShell EncodedCommand aliases and separator forms, including -e, so approval evaluation remains fail-closed.\n\nValidation: local ARM64 build passed; Shared tests 1319 passed / 20 skipped; Tray tests 466 passed; remote CI green.\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/OpenClaw.Shared/ExecShellWrapperParser.cs

@@ -135,8 +135,26 @@ internal static class ExecShellWrapperParser
         for (var i = 1; i < tokens.Length; i++)
         {
             var option = tokens[i];
-            if (option.Equals("-Command", StringComparison.OrdinalIgnoreCase) ||
-                option.Equals("-c", StringComparison.OrdinalIgnoreCase))
+
+            // Check for inline separator form first: -flag:value or -flag=value
+            var sepIdx = IndexOfFlagSeparator(option);
+            if (sepIdx > 0)
+            {
+                var flagPart = option[..sepIdx];
+                var valuePart = option[(sepIdx + 1)..];
+
+                if (IsCommandFlag(flagPart))
+                {
+                    return string.IsNullOrWhiteSpace(valuePart)
+                        ? ("", shell, "Shell wrapper payload was empty")
+                        : (valuePart, shell, null);
+                }
+
+                if (IsEncodedCommandFlag(flagPart))
+                    return DecodeEncodedPayload(valuePart, shell);
+            }
+
+            if (IsCommandFlag(option))
             {
                 var payload = string.Join(" ", tokens, i + 1, tokens.Length - i - 1).Trim();
                 return string.IsNullOrWhiteSpace(payload)
@@ -144,32 +162,68 @@ internal static class ExecShellWrapperParser
                     : (payload, shell, null);
             }
 
-            if (option.Equals("-EncodedCommand", StringComparison.OrdinalIgnoreCase) ||
-                option.Equals("-enc", StringComparison.OrdinalIgnoreCase) ||
-                option.Equals("-ec", StringComparison.OrdinalIgnoreCase))
+            if (IsEncodedCommandFlag(option))
             {
                 var encoded = i + 1 < tokens.Length ? tokens[i + 1] : null;
-                if (string.IsNullOrWhiteSpace(encoded))
-                    return ("", shell, "Shell wrapper payload was empty");
-
-                try
-                {
-                    var bytes = Convert.FromBase64String(encoded);
-                    var payload = Encoding.Unicode.GetString(bytes).Trim();
-                    return string.IsNullOrWhiteSpace(payload)
-                        ? ("", shell, "EncodedCommand decoded to an empty payload")
-                        : (payload, shell, null);
-                }
-                catch (FormatException)
-                {
-                    return ("", shell, "EncodedCommand could not be decoded");
-                }
+                return DecodeEncodedPayload(encoded, shell);
             }
         }
 
         return default;
     }
 
+    // Returns the index of the first ':' or '=' in a flag token (after the leading '-').
+    private static int IndexOfFlagSeparator(string token)
+    {
+        for (var i = 1; i < token.Length; i++)
+        {
+            if (token[i] == ':' || token[i] == '=')
+                return i;
+        }
+        return -1;
+    }
+
+    // Matches -Command and -c (documented PowerShell -Command aliases).
+    private static bool IsCommandFlag(string flag) =>
+        flag.Equals("-Command", StringComparison.OrdinalIgnoreCase) ||
+        flag.Equals("-c", StringComparison.OrdinalIgnoreCase);
+
+    // Matches -e/-ec aliases and all unique prefix abbreviations of -EncodedCommand.
+    // Windows PowerShell accepts -e as EncodedCommand despite the apparent ambiguity with
+    // -ExecutionPolicy, so the parser must fail closed and decode it.
+    private static bool IsEncodedCommandFlag(string flag)
+    {
+        if (flag.Equals("-e", StringComparison.OrdinalIgnoreCase))
+            return true;
+
+        if (flag.Equals("-ec", StringComparison.OrdinalIgnoreCase))
+            return true;
+
+        const string fullFlag = "-encodedcommand";
+        return flag.Length >= 3 &&  // minimum: -en
+               flag.Length <= fullFlag.Length &&
+               fullFlag.StartsWith(flag, StringComparison.OrdinalIgnoreCase);
+    }
+
+    private static (string? Payload, string? Shell, string? Error) DecodeEncodedPayload(string? encoded, string shell)
+    {
+        if (string.IsNullOrWhiteSpace(encoded))
+            return ("", shell, "Shell wrapper payload was empty");
+
+        try
+        {
+            var bytes = Convert.FromBase64String(encoded);
+            var payload = Encoding.Unicode.GetString(bytes).Trim();
+            return string.IsNullOrWhiteSpace(payload)
+                ? ("", shell, "EncodedCommand decoded to an empty payload")
+                : (payload, shell, null);
+        }
+        catch (FormatException)
+        {
+            return ("", shell, "EncodedCommand could not be decoded");
+        }
+    }
+
     private static List<string> SplitTopLevelCommands(string command)
     {
         var parts = new List<string>();

tests/OpenClaw.Shared.Tests/ExecShellWrapperParserTests.cs

@@ -138,6 +138,89 @@ public class ExecShellWrapperParserTests
         Assert.Contains(result.Targets, t => t.Command.Contains("Remove-Item"));
     }
 
+    // All unique prefix abbreviations of -EncodedCommand beyond -enc/-ec.
+    // Windows PowerShell also accepts -e as EncodedCommand, so include it to
+    // keep the shell-wrapper parser fail-closed.
+    [Theory]
+    [InlineData("-e")]
+    [InlineData("-en")]
+    [InlineData("-enco")]
+    [InlineData("-encod")]
+    [InlineData("-encode")]
+    [InlineData("-encoded")]
+    [InlineData("-encodedc")]
+    [InlineData("-encodedco")]
+    [InlineData("-encodedcom")]
+    [InlineData("-encodedcomm")]
+    [InlineData("-encodedcomma")]
+    [InlineData("-encodedcomman")]
+    [InlineData("-encodedcommand")]
+    public void Expand_Powershell_EncodedCommand_PrefixAbbreviation_Decodes(string flag)
+    {
+        var payload = "Get-ChildItem C:\\";
+        var encoded = Convert.ToBase64String(Encoding.Unicode.GetBytes(payload));
+        var result = Expand($"powershell {flag} {encoded}");
+        Assert.Null(result.Error);
+        Assert.Contains(result.Targets, t => t.Command.Contains("Get-ChildItem"));
+    }
+
+    // Inline separator forms: -enc:value and -enc=value
+    [Theory]
+    [InlineData("-enc")]
+    [InlineData("-EncodedCommand")]
+    [InlineData("-encodedcommand")]
+    public void Expand_Powershell_EncodedCommand_ColonSeparator_Decodes(string flagBase)
+    {
+        var payload = "Invoke-Something";
+        var encoded = Convert.ToBase64String(Encoding.Unicode.GetBytes(payload));
+        var result = Expand($"powershell {flagBase}:{encoded}");
+        Assert.Null(result.Error);
+        Assert.Contains(result.Targets, t => t.Command.Contains("Invoke-Something"));
+    }
+
+    [Theory]
+    [InlineData("-enc")]
+    [InlineData("-EncodedCommand")]
+    public void Expand_Powershell_EncodedCommand_EqualsSeparator_Decodes(string flagBase)
+    {
+        var payload = "Write-Host hi";
+        var encoded = Convert.ToBase64String(Encoding.Unicode.GetBytes(payload));
+        var result = Expand($"powershell {flagBase}={encoded}");
+        Assert.Null(result.Error);
+        Assert.Contains(result.Targets, t => t.Command.Contains("Write-Host"));
+    }
+
+    // -Command separator forms
+    [Theory]
+    [InlineData("-Command")]
+    [InlineData("-c")]
+    public void Expand_Powershell_Command_ColonSeparator_ExtractsPayload(string flagBase)
+    {
+        var result = Expand($"powershell {flagBase}:Get-Process");
+        Assert.Null(result.Error);
+        Assert.Contains(result.Targets, t => t.Command.Contains("Get-Process"));
+    }
+
+    [Theory]
+    [InlineData("-Command")]
+    [InlineData("-c")]
+    public void Expand_Powershell_Command_EqualsSeparator_ExtractsPayload(string flagBase)
+    {
+        var result = Expand($"powershell {flagBase}=Get-Date");
+        Assert.Null(result.Error);
+        Assert.Contains(result.Targets, t => t.Command.Contains("Get-Date"));
+    }
+
+    [Fact]
+    public void Expand_Powershell_SingleE_DecodesEncodedCommand()
+    {
+        var payload = "Get-ChildItem";
+        var encoded = Convert.ToBase64String(Encoding.Unicode.GetBytes(payload));
+        var result = Expand($"powershell -e {encoded}");
+        Assert.Null(result.Error);
+        Assert.Contains(result.Targets, t => t.Command.Contains("Get-ChildItem"));
+    }
+
     [Fact]
     public void Expand_Powershell_EncodedCommand_EmptyPayload_ReturnsError()
     {