dnschef-ng - DNSChef (NG) - DNS proxy for Penetration Testers a

项目说明

> [!NOTE]
> This is an updated of DNSChef originally written by

DNSChef is a highly configurable DNS proxy for Penetration Testers and Malware Analysts. A DNS proxy (aka "Fake DNS") is a tool used for application network traffic analysis among other uses. For example, a DNS proxy can be used to fake requests for "badguy.com" to point to a local machine for termination or interception instead of a real host somewhere on the Internet.

There are several DNS Proxies out there. Most will simply point all DNS queries a single IP address or implement only rudimentary filtering. DNSChef was de as part of a penetration test where there was a need for a more configurable system. As a result, DNSChef is cross-platform application capable of forging responses based on inclusive and exclusi lists, supporting multiple DNS record types, matching domains with wildcards, proxying true responses for nonmatching domains, defining external configuration files, IPv6 and many other features. You can find detailed explanation of each of the features and suggested uses below.

The use of DNS Proxy is recommended in situations where it is not possible to force an application to use some other proxy ser. For example, some mobile applications completely ignore OS HTTP Proxy settings. In these cases, the use of a DNS proxy server such as DNSChef will allow you to trick that application into forwarding connections to the desired destination.

New Features

Installing

To install the latest release you should use pipx (unless you're a piece of shit who enjoys sloppy stakes):

pipx install dnschef-ng

If you want the HTTP API (requires some extra dependencies):

pipx install dnschef-ng[api]

Install latest from Git using pipx:

pipx install git+

Install latest from Git using pipx with the deps for the HTTP API:

pipx install "git+]"

Setting up a DNS Proxy

Before you can start using DNSChef, you must configure your machine to use a DNS nameserver with the tool running on it. You ha options based on the operating system you are going to use:

If you do not have the ability to modify device's DNS settings manually, then you still ha options in techniques such as ARP Spoofing, Rogue DHCP and other creati.

At last you need to configure a fake service where DNSChef will point all of the requests. For example, if you are trying to intercept web traffic, you must bring up either a separate web ser on port 80 or set up a web proxy (e.g. Burp) to intercept traffic. DNSChef will point queries to your proxy/server host with properly configured services.

Running DNSChef

DNSChef is a cross-platform application de in Python which should run on most platforms which have a Python interpreter. This guide will concentrate on Unix en; however, all of the examples below were tested to work on Windows as well.

Let's get a taste of DNSChef with its most basic monitoring functionality. Execute the following command as root (required to start a server on port 53):

# ./dnschef.py

_ _ __
| | 0.2 | | / _|
__| |_ __ ___ ___| |__ ___| |_
/ _ | '_ \/ __|/ __| '_ \ / _ \ _|
| (_| | | | \__ \ (__| | | | __/ |
\__,_|_| |_|___/\___|_| |_|\___|_|


[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[*] No parameters were specified. Running in full proxy mode

Without any parameters, DNSChef will run in full proxy mode. This means that all requests will simply be forwarded to an upstream DNS server (8.8.8.8 by default) and returned back to the quering host. For example, let's query an "A" record for a domain and obser:

$ host -t A thesprawl.org
thesprawl.org has address 108.59.3.64

DNSChef will print the following log line showing time, source IP address, type of record requested and most importantly which name was queried:

[23:54:03] 127.0.0.1: proxying the response of type 'A' for thesprawl.org

This mode is useful for simple application monitoring where you need to figure out which domains it uses for its communications.

DNSChef has full support for IPv6 which can be activated using *-6* or *--ipv6** flags. It works exactly as IPv4 mode with the exception that default listening interface is switched to ::1 and default DNS server is switched to 2001:4860:4860::8888. Here is a sample output:

# ./dnschef.py -6
_ _ __
| | 0.2 | | / _|
__| |_ __ ___ ___| |__ ___| |_
/ _ | '_ \/ __|/ __| '_ \ / _ \ _|
| (_| | | | \__ \ (__| | | | __/ |
\__,_|_| |_|___/\___|_| |_|\___|_|

[*] Using IPv6 mode.
[*] DNSChef started on interface: ::1
[*] Using the following nameservers: 2001:4860:4860::8888
[*] No parameters were specified. Running in full proxy mode
[00:35:44] ::1: proxying the response of type 'A' for thesprawl.org
[00:35:44] ::1: proxying the response of type 'AAAA' for thesprawl.org
[00:35:44] ::1: proxying the response of type 'MX' for thesprawl.org

NOTE: By default, DNSChef creates a UDP listener. You can use TCP instead with the *--tcp* argument discussed later.

Running the DNSChef HTTP API

> [!WARNING]
> The API has no authentication. Allow/deny access at the network le security groups, iptables, firewall etc..

u dnschef.api:app

You can then view the OpenAPI documentation at

Intercept all responses

Now, that you know how to start DNSChef let's configure it to fake all replies to point to 127.0.0.1 using the *--fakeip* parameter:

# ./dnschef.py --fakeip 127.0.0.1 -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[*] Cooking all A replies to point to 127.0.0.1
[23:55:57] 127.0.0.1: cooking the response of type 'A' for google.com to 127.0.0.1
[23:55:57] 127.0.0.1: proxying the response of type 'AAAA' for google.com
[23:55:57] 127.0.0.1: proxying the response of type 'MX' for google.com

In the abo you an see that DNSChef was configured to proxy all requests to 127.0.0.1. The first line of log at 08:11:23 shows that we have "cooked" the "A" record response to point to 127.0.0.1. However, further requests for 'AAAA' and 'MX' records are simply proxied from a real DNS server. Let's see the output from requesting program:

$ host google.com localhost
google.com has address 127.0.0.1
google.com has IPv6 address 2001:4860:4001:803::1001
google.com mail is handled by 10 aspmx.l.google.com.
google.com mail is handled by 40 alt3.aspmx.l.google.com.
google.com mail is handled by 30 alt2.aspmx.l.google.com.
google.com mail is handled by 20 alt1.aspmx.l.google.com.
google.com mail is handled by 50 alt4.aspmx.l.google.com.

As you can see the program was tricked to use 127.0.0.1 for the IPv4 address. However, the information obtained from IPv6 (AAAA) and mail (MX) records appears completely legitimate. The goal of DNSChef is to have the least impact on the correct operation of the program, so if an application relies on a specific mailserver it will correctly obtain one through this proxied request.

Let's fake one more request to illustrate how to target multiple records at the same time:

# ./dnschef.py --fakeip 127.0.0.1 --fakeipv6 ::1 -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[*] Cooking all A replies to point to 127.0.0.1
[*] Cooking all AAAA replies to point to ::1
[00:02:14] 127.0.0.1: cooking the response of type 'A' for google.com to 127.0.0.1
[00:02:14] 127.0.0.1: cooking the response of type 'AAAA' for google.com to ::1
[00:02:14] 127.0.0.1: proxying the response of type 'MX' for google.com

In addition to the --fakeip flag, I have now specified --fakeipv6 designed to fake 'AAAA' record queries. Here is an updated program output:

$ host google.com localhost
google.com has address 127.0.0.1
google.com has IPv6 address ::1
google.com mail is handled by 10 aspmx.l.google.com.
google.com mail is handled by 40 alt3.aspmx.l.google.com.
google.com mail is handled by 30 alt2.aspmx.l.google.com.
google.com mail is handled by 20 alt1.aspmx.l.google.com.
google.com mail is handled by 50 alt4.aspmx.l.google.com.

Once more all of the records not explicitly o by the application were proxied and returned from the real DNS server. However, IPv4 (A) and IPv6 (AAAA) were both faked to point to a local machine.

DNSChef supports multiple record types:

Record | Description | Argument | Example
---|---|---|---
A | IPv4 address |--fakeip | --fakeip 192.0.2.1
AAAA | IPv6 address |--fakeipv6 | --fakeipv6 2001:db8::1
MX | Mail server |--fakemail | --fakemail mail.fake.com
CNAME | CNAME record |--fakealias| --fakealias www.fake.com
NS | Name server |--fakens | --fakens ns.fake.com

NOTE: For usability not all DNS record types are exposed on the command line. Additional records such as PTR, TXT, SOA, etc. can be specified using the --file flag and an appropriate record header. See the external definitions file section below for details.

At last let's observe how the application handles queries of type ANY:

# ./dnschef.py --fakeip 127.0.0.1 --fakeipv6 ::1 --fakemail mail.fake.com --fakealias www.fake.com --fakens ns.fake.com -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[*] Cooking all A replies to point to 127.0.0.1
[*] Cooking all AAAA replies to point to ::1
[*] Cooking all MX replies to point to mail.fake.com
[*] Cooking all CNAME replies to point to www.fake.com
[*] Cooking all NS replies to point to ns.fake.com
[00:17:29] 127.0.0.1: cooking the response of type 'ANY' for google.com with all known fake records.

DNS ANY record queries results in DNSChef returning every faked record that it knows about for an applicable domain. Here is the output that the program will see:

# host -t ANY google.com localhost
google.com has address 127.0.0.1
google.com has IPv6 address ::1
google.com mail is handled by 10 mail.fake.com.
google.com is an alias for www.fake.com.
google.com name server ns.fake.com.

Filtering domains

Using the abo, consider you only want to intercept requests for *thesprawl.org* and lea to all other domains such as *webfaction.com* without modification. You can use the *--fakedomains* parameter as illustrated below:

# ./dnschef.py --fakeip 127.0.0.1 --fakedomains thesprawl.org -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[*] Cooking replies to point to 127.0.0.1 matching: thesprawl.org
[00:23:37] 127.0.0.1: cooking the response of type 'A' for thesprawl.org to 127.0.0.1
[00:23:52] 127.0.0.1: proxying the response of type 'A' for mx9.webfaction.com

From the abo the request for *thesprawl.org* was faked; however, the request for *mx9.webfaction.com* was left alone. Filtering domains is very useful when you attempt to isolate a single application without breaking the rest.

NOTE: DNSChef will not whether the domain exists or not before faking the response. If you ha a domain it will always resolve to a fake value whether it really exists or not.

Reverse filtering

In another situation you may need to fake responses for all requests except a defined list of domains. You can accomplish this task using the *--truedomains* parameter as follows:

# ./dnschef.py --fakeip 127.0.0.1 --truedomains thesprawl.org,*.webfaction.com -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[*] Cooking replies to point to 127.0.0.1 not matching: *.webfaction.com, thesprawl.org
[00:27:57] 127.0.0.1: proxying the response of type 'A' for mx9.webfaction.com
[00:28:05] 127.0.0.1: cooking the response of type 'A' for google.com to 127.0.0.1

There are several things going on in the abo. First notice the use of a wildcard (*). All domains matching *.webfaction.com will be reverse matched and resolved to their true . The request for 'google.com' returned 127.0.0.1 because it was not on the list of excluded domains.

NOTE: Wildcards are position specific. A mask of type *.thesprawl.org will match www.thesprawl.org but not www.test.thesprawl.org. However, a mask of type *.*.thesprawl.org will match thesprawl.org, www.thesprawl.org and www.test.thesprawl.org.

External definitions file

There may be situations where defining a single fake DNS record for all matching domains may not be sufficient. You can use an external file with a collection of DOMAIN=RECORD pairs defining exactly where you want the request to go.

For example, let create the following definitions file and call it dnschef.toml:

Notice the section header [A], it defines the record type to DNSChef. Now let's carefully observe the output of multiple queries:

# ./dnschef.py --file dnschef.toml -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[+] Cooking A replies for domain *.google.com with '192.0.2.1'
[+] Cooking A replies for domain thesprawl.org with '192.0.2.2'
[+] Cooking A replies for domain *.wordpress.* with '192.0.2.3'
[00:43:54] 127.0.0.1: cooking the response of type 'A' for google.com to 192.0.2.1
[00:44:05] 127.0.0.1: cooking the response of type 'A' for www.google.com to 192.0.2.1
[00:44:19] 127.0.0.1: cooking the response of type 'A' for thesprawl.org to 192.0.2.2
[00:44:29] 127.0.0.1: proxying the response of type 'A' for www.thesprawl.org
[00:44:40] 127.0.0.1: cooking the response of type 'A' for www.wordpress.org to 192.0.2.3
[00:44:51] 127.0.0.1: cooking the response of type 'A' for wordpress.com to 192.0.2.3
[00:45:02] 127.0.0.1: proxying the response of type 'A' for slashdot.org

Both *google.com* and *www.google.com* matched the *\*.google.com* entry and correctly resolved to *192.0.2.1*. On the other hand *www.thesprawl.org* request was simply proxied instead of being modified. At last all of *wordpress.com*, *www.wordpress.org*, etc. matched the *\*.wordpress.\** mask and correctly resolved to *192.0.2.3*. At last an undefined *slashdot.org* query was simply proxied with a real response.

You can specify section headers for all other supported DNS record types including the ones not explicitly exposed on the command line: [A], [AAAA], [MX], [NS], [CNAME], [PTR], [NAPTR] and [SOA]. For example, let's define a new [PTR] section in the dnschef.toml file:

Let's obser's behavior with this new record type:

./dnschef.py --file dnschef.toml -q
[sudo] password for iphelix:
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[+] Cooking PTR replies for domain *.2.0.192.in-addr.arpa with 'fake.com'
[00:11:34] 127.0.0.1: cooking the response of type 'PTR' for 1.2.0.192.in-addr.arpa to fake.com

And here is what a client might see when performing reverse DNS queries:

$ host 192.0.2.1 localhost
1.2.0.192.in-addr.arpa domain name pointer fake.com.

Some records require exact formatting. Good examples are SOA and NAPTR

See sample dnschef.toml file for additional examples.

File Staging

DNSChef can "stage" any file through DNS. Currently file staging is only supported with A, AAAA and TXT records (will be adding more). To instruct DNSChef to stage a file, add the following section to your dnschef.toml:

> [!NOTE]
> The chunk_size setting is optional and it's behavior is highly dependent on the query type. Example: As A queries return an IPv4 address, the maximum allowed chunk_size is 4 bytes. Setting the chunk_size to anything above 4 will be ignored.

An A query to *.wat.org containing a number in the DNS name will now return the corresponding chunk of the file. E.g the query ns0.wat.org will return an IPv4 address containing the first chunk of the file (4 bytes). A query for test1.wat.org will return the second chunk of the file etc...

When using wildcard domains like the abo, the "chunk" numbers can be placed anywhere and don't have to be put together. E.g an A query for 1aliens2.wat.org will return the 12th chunk of the file.

TXT records support additional options for file staging as they allow more flexibility:

With this configuration, any TXT query to ns*.dungbeetle.org will return a chunk of our file located locally on the filesystem at ~/payload.exe.

The response_format and response_prefix_pool settings are optional but allow you to further customize the DNS TXT response.

The response_format setting defines the format of the TXT response:

With the abo, a TXT query to ns1.dungbeetle.org will return the following response:

If you perform another TXT query (e.g. ns10.dungbeetle.org), you'll see that the prefix will change:

Ad Filtering

You can mix and match input from a file and command line. For example the following command uses both --file and --fakedomains parameters:

# ./dnschef.py --file dnschef.toml --fakeip 6.6.6.6 --fakedomains=thesprawl.org,slashdot.org -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[+] Cooking A replies for domain *.google.com with '192.0.2.1'
[+] Cooking A replies for domain thesprawl.org with '192.0.2.2'
[+] Cooking A replies for domain *.wordpress.* with '192.0.2.3'
[*] Cooking A replies to point to 6.6.6.6 matching: *.wordpress.*, *.google.com, thesprawl.org
[*] Cooking A replies to point to 6.6.6.6 matching: slashdot.org, *.wordpress.*, *.google.com, thesprawl.org
[00:49:05] 127.0.0.1: cooking the response of type 'A' for google.com to 192.0.2.1
[00:49:15] 127.0.0.1: cooking the response of type 'A' for slashdot.org to 6.6.6.6
[00:49:31] 127.0.0.1: cooking the response of type 'A' for thesprawl.org to 6.6.6.6
[00:50:08] 127.0.0.1: proxying the response of type 'A' for tor.com

Notice the definition for *thesprawl.org* in the command line parameter took precedence over *dnschef.toml*. This could be useful if you want to o in the configuration file. slashdot.org still resolves to the fake IP address because it was specified in the *--fakedomains* parameter. tor.com request is simply proxied since it was not specified in either command line or the configuration file.

Other configurations

For security reasons, DNSChef listens on a local 127.0.0.1 (or ::1 for IPv6) interface by default. You can make DNSChef listen on another interface using the *--interface* parameter:

# ./dnschef.py --interface 0.0.0.0 -q
[*] DNSChef started on interface: 0.0.0.0
[*] Using the following nameservers: 8.8.8.8
[*] No parameters were specified. Running in full proxy mode
[00:50:53] 192.0.2.105: proxying the response of type 'A' for thesprawl.org

or for IPv6:

# ./dnschef.py -6 --interface :: -q
[*] Using IPv6 mode.
[*] DNSChef started on interface: ::
[*] Using the following nameservers: 2001:4860:4860::8888
[*] No parameters were specified. Running in full proxy mode
[00:57:46] 2001:db8::105: proxying the response of type 'A' for thesprawl.org

By default, DNSChef uses Google's public DNS server to make proxy requests. However, you can define a custom list of nameservers using the *--nameservers* parameter:

# ./dnschef.py --nameservers 4.2.2.1,4.2.2.2 -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 4.2.2.1, 4.2.2.2
[*] No parameters were specified. Running in full proxy mode
[00:55:08] 127.0.0.1: proxying the response of type 'A' for thesprawl.org

It is possible to specify non-standard nameserver port using IP#PORT notation:

# ./dnschef.py --nameservers 192.0.2.2#5353 -q
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 192.0.2.2#5353
[*] No parameters were specified. Running in full proxy mode
[02:03:12] 127.0.0.1: proxying the response of type 'A' for thesprawl.org

At the same time it is possible to start DNSChef itself on an alternative port using the -p port# parameter:

# ./dnschef.py -p 5353 -q
[*] Listening on an alternative port 5353
[*] DNSChef started on interface: 127.0.0.1
[*] Using the following nameservers: 8.8.8.8
[*] No parameters were specified. Running in full proxy mode

DNS protocol can be used over UDP (default) or TCP. DNSChef implements a TCP mode which can be activated with the --tcp flag.

项目信息

开发语言：Python

Star 数：174

技术要点

该项目属于病毒分析方向的开源资源，代码结构清晰，适合安全研究人员学习参考。项目围绕DNSChef (NG) - DNS proxy for Penetration Testers and Malware Analysts 展开，提供了可运行的实现，对理解相关安全机制、工具原理与攻防技术具有较高的研究价值。

从技术实现角度看，此类项目的核心在于对底层原理的深入理解与工程化落地。开发者在研究过程中可以结合官方文档与社区讨论，梳理项目的初始化流程、核心模块职责与数据流转，逐步掌握其中的技术细节与设计思路。

使用与学习建议

1. 下载源码压缩包，解压到本地环境。

2. 根据项目类型准备对应的运行环境与依赖。

3. 按照 README 中的步骤完成配置与部署。

4. 在隔离的测试环境中运行验证，避免影响生产系统。

免责声明

本资源来源于开源社区，仅供安全研究、技术学习与合法授权范围内的攻防演练使用，请勿用于任何非法或侵害他人权益的用途。使用本项目产生的一切后果由使用者自行承担。