peass-ng/PEASS-ng · error · EndOfStreamException

DEF length object truncated by

Error message

DEF length  object truncated by 

What it means

DefiniteLengthInputStream.ToArray reads the declared number of bytes via Streams.ReadFully; if the underlying stream ends early, the remaining count is nonzero and EndOfStreamException 'DEF length N object truncated by M' is thrown. The declared definite-length object could not be fully read.

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/asn1/DefiniteLengthInputStream.cs:105

			if ((_remaining -= Streams.ReadFully(_in, buf)) != 0)
				throw new EndOfStreamException("DEF length " + _originalLength + " object truncated by " + _remaining);
			SetParentEofDetect(true);
		}

		internal byte[] ToArray()
		{
			if (_remaining == 0)
				return EmptyBytes;

			// make sure it's safe to do this!
			int limit = Limit;
			if (_remaining >= limit)
				throw new IOException("corrupted stream - out of bounds length found: " + _remaining + " >= " + limit);

			byte[] bytes = new byte[_remaining];
			if ((_remaining -= Streams.ReadFully(_in, bytes)) != 0)
				throw new EndOfStreamException("DEF length " + _originalLength + " object truncated by " + _remaining);
			SetParentEofDetect(true);
			return bytes;
		}
	}
}

View on GitHub (pinned to 53fb989abc)

Solutions

1. Ensure the complete encoded object is available before parsing (buffer the stream fully first)
2. Check file size / transfer completeness; re-download the blob
3. When reading from sockets, loop reading until the expected length is received or use a higher-level protocol framing
4. Catch EndOfStreamException and report the data as truncated/corrupt

Example fix

// before
Asn1Object o = Asn1Object.FromStream(networkStream); // may end early
// after
using (var ms = new MemoryStream())
{
    networkStream.CopyTo(ms); // or read exactly N bytes from framed protocol
    ms.Position = 0;
    Asn1Object o = Asn1Object.FromStream(ms); // complete data buffered
}

// ensure all declared bytes are present before parsing
bool IsComplete(byte[] data) { int i = 1; int n = data[1] & 0x7f; if ((data[1] & 0x80) != 0) { int len = data[1] & 0x7f; long v = 0; for (int k = 0; k < len; k++) v = (v << 8) | data[2 + k]; n = checked((int)v); i = 2 + len; } return data.Length >= i + n; }

try { return Asn1Object.FromStream(ms); }
catch (EndOfStreamException ex) { throw new InvalidDataException("ASN.1 object truncated: " + ex.Message, ex); }

When it happens

Trigger: An ASN.1 object header declares a definite length N, but ReadFully obtains fewer than N bytes because the stream is truncated mid-object (network drop, partial file, read past a buffer boundary).

Common situations: Parsing truncated downloads of certificates/PKCS#12/signed data; reading ASN.1 from a network stream that closed early; slicing a byte[] too short before wrapping in MemoryStream.

Related errors

• corrupted stream - out of bounds length found:
• unknown object encountered in constructed OCTET STRING:
• unknown tag {tagNo} encountered
• unexpected end-of-contents marker
• indefinite-length primitive encoding encountered

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/4a4ede2e74d83319. Report an issue: GitHub.