{"record":{"id":"07ec2a5cb9988070","repo":"peass-ng/PEASS-ng","slug":"cannot-recognise-object-in-byte-array","errorCode":null,"errorMessage":"cannot recognise object in byte array","messagePattern":"cannot recognise object in byte array","errorType":"exception","errorClass":"IOException","httpStatus":null,"severity":"error","filePath":"winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/asn1/Asn1Object.cs","lineNumber":29,"sourceCode":"\t\t/// <returns>The base ASN.1 object represented by the byte array.</returns>\n\t\t/// <exception cref=\"IOException\">\n\t\t/// If there is a problem parsing the data, or parsing an object did not exhaust the available data.\n\t\t/// </exception>\n\t\tpublic static Asn1Object FromByteArray(\n\t\t\tbyte[] data)\n\t\t{\n\t\t\ttry\n\t\t\t{\n\t\t\t\tMemoryStream input = new MemoryStream(data, false);\n\t\t\t\tAsn1InputStream asn1 = new Asn1InputStream(input, data.Length);\n\t\t\t\tAsn1Object result = asn1.ReadObject();\n\t\t\t\tif (input.Position != input.Length)\n\t\t\t\t\tthrow new IOException(\"extra data found after object\");\n\t\t\t\treturn result;\n\t\t\t}\n\t\t\tcatch (InvalidCastException)\n\t\t\t{\n\t\t\t\tthrow new IOException(\"cannot recognise object in byte array\");\n\t\t\t}\n\t\t}\n\n\t\t/// <summary>Read a base ASN.1 object from a stream.</summary>\n\t\t/// <param name=\"inStr\">The stream to parse.</param>\n\t\t/// <returns>The base ASN.1 object represented by the byte array.</returns>\n\t\t/// <exception cref=\"IOException\">If there is a problem parsing the data.</exception>\n\t\tpublic static Asn1Object FromStream(\n\t\t\tStream inStr)\n\t\t{\n\t\t\ttry\n\t\t\t{\n\t\t\t\treturn new Asn1InputStream(inStr).ReadObject();\n\t\t\t}\n\t\t\tcatch (InvalidCastException)\n\t\t\t{\n\t\t\t\tthrow new IOException(\"cannot recognise object in stream\");\n\t\t\t}","sourceCodeStart":11,"sourceCodeEnd":47,"githubUrl":"https://github.com/peass-ng/PEASS-ng/blob/53fb989abc2219826385683a6fee826bd6cd38d6/winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/asn1/Asn1Object.cs#L11-L47","documentation":"FromByteArray wraps parsing in a catch for InvalidCastException (from GetInstance-style casts inside decoding) and rethrows it as IOException 'cannot recognise object in byte array'. The bytes did not decode into a recognizable ASN.1 object.","triggerScenarios":"Input that is not valid ASN.1/DER at all — e.g. PEM text, a random key blob, or bytes whose leading tag/length bytes cause an invalid cast during object construction.","commonSituations":"Forgetting to base64-decode PEM before parsing; passing a raw key (e.g. RSA Parameters or PKCS#8 without proper handling) to an ASN.1 API; wrong file format (DER vs PEM vs raw).","solutions":["Confirm the input is binary DER; if it is PEM, strip headers and Convert.FromBase64String first","Check the format your key/cert actually is (PKCS#1 vs PKCS#8 vs X.509) and use the right parser","Hex-dump the first bytes: a DER object starts with a valid tag byte (e.g. 0x30 for SEQUENCE)","Catch IOException and fall back to alternative parsers or report a format error"],"exampleFix":"// before\nstring pem = File.ReadAllText(\"cert.pem\");\nAsn1Object o = Asn1Object.FromByteArray(Encoding.UTF8.GetBytes(pem));\n// after\nstring b64 = pem.Replace(\"-----BEGIN CERTIFICATE-----\", \"\")\n                .Replace(\"-----END CERTIFICATE-----\", \"\");\nAsn1Object o = Asn1Object.FromByteArray(Convert.FromBase64String(b64));","handlingStrategy":"validation","validationCode":"static bool LooksLikeBinaryDer(byte[] data)\n{\n    if (data == null || data.Length < 2) return false;\n    if (data[0] == '-' || (data[0] >= 32 && data[0] < 127 && data[1] >= 32 && data[1] < 127))\n        return false; // ASCII/PEM text, not DER\n    return true; // plausible binary\n}","typeGuard":null,"tryCatchPattern":"try { Asn1Object o = Asn1Object.FromByteArray(data); }\ncatch (IOException ex) when (ex.Message.Contains(\"cannot recognise\"))\n{\n    // not valid ASN.1: check PEM vs DER vs raw key format\n}","preventionTips":["Base64-decode PEM bodies before any ASN.1 API call","Confirm certificate/key encoding (PEM, DER, PKCS#1, PKCS#8) upfront","Sanity-check the first byte is a valid ASN.1 tag (e.g. 0x30)"],"tags":["asn1","der","format","pem"],"backgroundTag":"invalid-asn1-input","analyzedSha":"53fb989abc2219826385683a6fee826bd6cd38d6","analyzedAt":"2026-09-02T04:25:09.259Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-09T11:17:12.671Z"}