CVE-2023-51764 PoC — Postfix 安全漏洞

Source

https://github.com/duy-31/CVE-2023-51764

Associated Vulnerability

Title:Postfix 安全漏洞 (CVE-2023-51764)
Description:Postfix through 3.8.5 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports <LF>.<CR><LF> but some other popular e-mail servers do not. To prevent attack variants (by always disallowing <LF> without <CR>), a different solution is required, such as the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.

Description

Postfix SMTP Smuggling - Expect Script POC

Readme

# CVE-2023-51764
Postfix SMTP Smuggling - Expect Script POC

send an email that is legitimate, but inside the email there is many others emails (different senders, recipients, subjet, etc).
The initial email is check for SPF/DKIM/DMARC, the others inside are not !

usage: ./cve-2023-51764.sh mx.fqdn port
<br>./cve-2023-51764.sh mail.mydomain.com 25

![image](https://github.com/duy-31/CVE-2023-51764/assets/20819326/e6a0175f-b5ed-4022-aa06-386599984df3)


notes:
chmod +x cve-2023-51764.sh
<br> require app expect
<br> require legitimate ip sender and email sender (to pass SPF, DKIM, DMARC)

result:

![image](https://github.com/duy-31/CVE-2023-51764/assets/20819326/82d31732-8548-493c-98e8-28cadc571107)


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Kudos: https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide
<br>Workaround/Fix: https://www.postfix.org/smtp-smuggling.html

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more about me ;) https://www.linkedin.com/in/duy-huan-bui/

⚠️ Disclaimer:
IMPORTANT: This script is provided for educational, ethical testing, and lawful use ONLY. Do not use it on any system or network without explicit permission. Unauthorized access to computer systems and networks is illegal, and users caught performing unauthorized activities are subject to legal actions. The author is NOT responsible for any damage caused by the misuse of this script.

File Snapshot


 [4.0K]  /data/pocs/e76d0a8e321b7b3503d100f579479da271416bde
├── [2.0K]  cve-2023-51764.sh
└── [1.3K]  README.md

0 directories, 2 files

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