Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Learning Aid - Top Base64 Encodings Table

Learning Aid - Top Base64 Encodings Table

Base64 Code Mnemonic Aid Decoded* Description
JAB 🗣 Jabber $. Variable declaration (UTF-16)
TVq 📺 Television MZ MZ header
SUVY 🚙 SUV IEX PowerShell Invoke Expression
SQBFAF 🐣 Squab favorite I.E. PowerShell Invoke Expression (UTF-16)
SQBuAH 🐣 Squab uahhh I.n. PowerShell Invoke string (UTF-16) e.g. Invoke-Mimikatz
PAA 💪 "Pah!" <. Often used by Emotet (UTF-16)
cwBhA 🦁 Chewbaka s.a. Often used in malicious droppers (UTF-16) 'sal' instead of 'var'
aWV4 😲 Awe version 4 iex PowerShell Invoke Expression
aQBlA 💦 Aqua Blah (aquaplaning) i.e. PowerShell Invoke Expression (UTF-16)
R2V0 🤖 R2D2 but version 0 Get Often used to obfuscate imports like GetCurrentThreadId
dmFy 👹 defy / demonify var Variable declaration
dgBhA debugger + high availability v.a. Variable declaration (UTF-16)
dXNpbm Dixon problem usin Often found in compile after delivery attacks
H4sIA 🚁 HForce (Helicopter Force) I agree gzip magic bytes (0x1f8b), e.g. echo 'test' | gzip -cf | base64
Y21k 🎆 Year 21k bug cmd As used in cmd.exe /c wscript.exe or the like
IAB 🥱 I am bored s wide lower case s, often something like sEt-iTem
cABhAH 🕋 Kaaba p.a. wide formatted param
Qzpc 🖥 Quiz PC C:\ Root of Windows partition (upper case)
Yzpc 🖥 Yes PC c:\ Root of Windows partition (lower case)
UEs 🏬 Upper East Side PK ZIP, Office documents
ey 🗣 Hey {  Indicates JSON data

* the . stands for 0x00 found in UTF-16 encoded text

Cyber Chef Recipe

https://gchq.github.io/CyberChef/#recipe=Fork('%5C%5Cn','%5C%5Cn',false)From_Base64('A-Za-z0-9%2B/%3D',true)&input=SkFCClRWcQpQQUEKU1VWWQpTUUJGQUYKYVdWNAphUUJsQQpSMlYwCmRtRnkKZGdCaEEKY3dCaEEKZFhOcGJtCkg0c0lBRldXc2wwQUF5dEpMUzdoQWdER05iazdCUUFBQUE9PQ

References

Tweet

Tweet and Thread https://twitter.com/cyb3rops/status/1187341941794660354

JAB

https://www.hybrid-analysis.com/sample/ce0415b6661ef66bbedb69896ad1ece9ee4e6dfde9925e9612aec7bbf1cb7bc5?environmentId=100

PAA

Emotet process command line https://app.any.run/tasks/dfba6d53-7a93-4d8b-86ba-4e737ad06b06/

cwBha

Explanation https://threat.tevora.com/5-minute-forensics-decoding-powershell-payloads/

Sample https://www.hybrid-analysis.com/sample/b744129bfe54de8b36d7556ddfcc55d0be213129041aacf52b7d2f57012caa60?environmentId=100

@srcr
Copy link

srcr commented Oct 15, 2020

should MITRE ATT4CK be changed to MITRE ATT&CK? Very nice list though. Danke

@Neo23x0
Copy link
Author

Neo23x0 commented Oct 15, 2020

I'll remove the MITRE reference completely. Don't want that anyone tells me that it lacks a (r) character.

@ohader
Copy link

ohader commented Mar 9, 2022

Please add YTo and Tzo, start of a serialized array and object in PHP (a: and O:), good indicator when searching for insecure deserialization vulns. PoC at https://3v4l.org/9PI63

@dc-secureworks
Copy link

dc-secureworks commented Apr 7, 2022

Please mention that these encodings only hold at the start of the encoded string and will not work consistently at other positions. Most people aren't aware of the 3 byte chunks used to encode base64 and the 3 encodings repetition you get by shifting one byte at a time. Also IAB decodes to 0x20 0x00 not 0x73 0x00.
Here's an example of determining the consistent subset of an encoded string at the 3 offsets. (wide "s" used) https://gchq.github.io/CyberChef/#recipe=Fork('%5C%5Cn','%5C%5Cn',false)From_Hex('Auto')To_Base64('A-Za-z0-9%2B/%3D')&input=NzMgMDAgMDAgMDAKNzMgMDAgNzcgNzcKNzMgMDAgRkYgRkYKMDAgNzMgMDAgMDAgMDAKNzcgNzMgMDAgNzcgNzcKRkYgNzMgMDAgRkYgRkYKMDAgMDAgNzMgMDAgMDAgMDAgMDAKNzcgNzcgNzMgMDAgNzcgNzcgNzcKRkYgRkYgNzMgMDAgRkYgRkYgRkYKMDAgMDAgMDAgNzMgMDAgMDAgMDAgMDAKNzcgNzcgNzcgNzMgMDAgNzcgNzcgNzcKRkYgRkYgRkYgNzMgMDAgRkYgRkYgRkYKMDAgMDAgMDAgMDAgNzMgMDAgMDAgMDAgMDAKNzcgNzcgNzcgNzcgNzMgMDAgNzcgNzcgNzcKRkZGRiBGRiBGRiA3MyAwMCBGRiBGRiBGRgoK
Unless you're only checking the start of a buffer you'll need to trim a bit off the front and back to safely detect the consistent substring of what you're looking for. From the example of wide "s" you have cw, MA, zA. I added extra shifts in Cyberchef to illustrate the cycle and how the pattern comes back every 3rd byte.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment