fortra/impacket

TDS: Unknown Token 0 / ac

Open

#879 opened on Jun 9, 2020

View on GitHub
 (1 comment) (0 reactions) (0 assignees)Python (12,244 stars) (3,421 forks)batch import
enhancementhelp wanted

Description

Configuration

impacket version: 0.9.21 Python version: 3.7.7 Target OS: Ubuntu 18.04

Debug Output With Command String

i.e.
smbexec -debug domain/user:password@127.0.0.1

>>> tds.MSSQL('bla').parseReply(b"\xac\x0d\x00\x00\x01\x00\x00\x00\x00\x26\x04\x04\x0c\x00\x00\x00\xfe\x00\x00\xe0\x00\x00\x00\x00\x00")
ERROR:impacket:Unknown Token ac
{}

Additional context

This buffer is a 0xac token type taken from a pcap of TDS version 7.1. I expected token values 0xac (TDS_PARAM_TOKEN) and 0x00 (TVP_END_TOKEN) to be parsed.

Contributor guide

Tech stack
python
Domain
backenddatabase
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic PythonUnderstanding of network protocols
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65
Research direction
The issue reports an unknown token 0xac in TDS protocol parsing. Examine the impacket source code, likely in the tds module (e.g., impacket/tds.py), to see how existing tokens are parsed. Add parsing logic for token 0xac (TDS PARAM TOKEN) and 0x00 (TVP END TOKEN) following the pattern of similar tokens. Test with the provided byte sequence to verify parsing.