peass-ng/PEASS-ng · error · ArgumentException

byte value should have 1 byte in it

Error message

byte value should have 1 byte in it

What it means

The DerBoolean(byte[]) constructor requires exactly one content octet, per the ASN.1 BOOLEAN encoding (a single byte where 0xFF is true and 0x00 is false). A byte array of any other length is invalid and triggers this ArgumentException.

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/asn1/DerBoolean.cs:66

        public static DerBoolean GetInstance(
            Asn1TaggedObject obj,
            bool isExplicit)
        {
            Asn1Object o = obj.GetObject();

            if (isExplicit || o is DerBoolean)
            {
                return GetInstance(o);
            }

            return FromOctetString(((Asn1OctetString)o).GetOctets());
        }

        public DerBoolean(
            byte[] val)
        {
            if (val.Length != 1)
                throw new ArgumentException("byte value should have 1 byte in it", "val");

            // TODO Are there any constraints on the possible byte values?
            this.value = val[0];
        }

        private DerBoolean(
            bool value)
        {
            this.value = value ? (byte)0xff : (byte)0;
        }

        public bool IsTrue
        {
            get { return value != 0; }
        }

        internal override void Encode(
            DerOutputStream derOut)

View on GitHub (pinned to 53fb989abc)

Solutions

1. Validate val.Length == 1 before calling the constructor
2. If the source is DER content, verify the length octet and slice exactly one byte
3. If multiple bytes are meaningful, the data is not a BOOLEAN - parse it as the correct ASN.1 type instead
4. Catch ArgumentException and reject the record as malformed

Example fix

// before
var b = new DerBoolean(contentBytes);
// after
if (contentBytes.Length != 1) throw new FormatException("BOOLEAN must be 1 byte");
var b = new DerBoolean(contentBytes);

if (val == null || val.Length != 1) throw new FormatException("BOOLEAN content must be exactly 1 byte");

bool IsValidBooleanBytes(byte[] b) => b != null && b.Length == 1;

try { var b = new DerBoolean(val); }
catch (ArgumentException) { /* reject record as malformed */ }

When it happens

Trigger: Constructing DerBoolean directly from a byte[] whose Length != 1, e.g. passing multi-byte content from a malformed BER/DER record or from user-supplied bytes.

Common situations: Hand-crafting ASN.1 structures; decoding corrupted or non-conformant DER data where the BOOLEAN content length field is wrong; slicing errors that grab surrounding bytes.

Related errors

• unknown object encountered in constructed OCTET STRING:
• unknown tag {tagNo} encountered
• DER length more than 4 bytes:
• illegal object in GetInstance:
• BOOLEAN value should have 1 byte in it

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/d6b3d5247450359e. Report an issue: GitHub.