5.3
MEDIUM
CVE-2023-51764
Postfix SMTP Smuggling Vulnerability
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.

INFO

Published Date :

Dec. 24, 2023, 5:15 a.m.

Last Modified :

June 10, 2024, 6:15 p.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

1.4

Exploitability Score :

3.9
Public PoC/Exploit Available at Github

CVE-2023-51764 has a 5 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2023-51764 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Redhat enterprise_linux
1 Fedoraproject fedora
1 Postfix postfix
: Total Affected Vendor : 3 | Products : 3
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2023-51764.

URL Resource
http://www.openwall.com/lists/oss-security/2023/12/24/1 Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2023/12/25/1 Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/05/09/3
https://access.redhat.com/security/cve/CVE-2023-51764 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2255563 Issue Tracking Third Party Advisory
https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html Technical Description
https://github.com/duy-31/CVE-2023-51764 Exploit Third Party Advisory
https://github.com/eeenvik1/CVE-2023-51764 Exploit Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00020.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JQ5WXFCW2N6G2PH3JXDTYW5PH5EBQEGO/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRLF5SOS7TP5N7FQSEK2NFNB44ISVTZC/
https://lwn.net/Articles/956533/
https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/ Technical Description Third Party Advisory
https://www.openwall.com/lists/oss-security/2024/01/22/1
https://www.postfix.org/announcements/postfix-3.8.5.html
https://www.postfix.org/smtp-smuggling.html Exploit Mitigation Vendor Advisory
https://www.youtube.com/watch?v=V8KPV96g1To Exploit

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
Double-q1015/CVE-2023-51764

CVE-2023-51764 poc

Shell

Updated: 10 months, 2 weeks ago
0 stars 0 fork 0 watcher
Born at : Jan. 5, 2024, 7:07 a.m. This repo has been linked 1 different CVEs too.
Profile Photo
d4op/CVE-2023-51764-POC

just idea, no cp pls

Python

Updated: 9 months, 4 weeks ago
1 stars 0 fork 0 watcher
Born at : Dec. 31, 2023, 2:33 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
eeenvik1/CVE-2023-51764

PoC CVE-2023-51764

cve

Python

Updated: 9 months, 3 weeks ago
3 stars 3 fork 3 watcher
Born at : Dec. 28, 2023, 6:20 a.m. This repo has been linked 2 different CVEs too.
Profile Photo
duy-31/CVE-2023-51764

Postfix SMTP Smuggling - Expect Script POC

Shell

Updated: 3 months, 1 week ago
25 stars 8 fork 8 watcher
Born at : Dec. 26, 2023, 5:02 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
hannob/smtpsmug

None

Python Shell

Updated: 4 months ago
94 stars 13 fork 13 watcher
Born at : Dec. 21, 2023, 8:13 p.m. This repo has been linked 3 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2023-51764 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2023-51764 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Jun. 10, 2024

    Action Type Old Value New Value
    Added Reference MITRE http://www.openwall.com/lists/oss-security/2024/05/09/3 [No types assigned]
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Jan. 30, 2024

    Action Type Old Value New Value
    Added Reference MITRE https://lists.debian.org/debian-lts-announce/2024/01/msg00020.html [No types assigned]
  • CVE Modified by [email protected]

    Jan. 22, 2024

    Action Type Old Value New Value
    Changed Description Postfix through 3.8.4 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: 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. 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.
    Added Reference MITRE https://www.openwall.com/lists/oss-security/2024/01/22/1 [No types assigned]
    Added Reference MITRE https://www.postfix.org/announcements/postfix-3.8.5.html [No types assigned]
  • CVE Modified by [email protected]

    Jan. 18, 2024

    Action Type Old Value New Value
    Added Reference MITRE https://lwn.net/Articles/956533/ [No types assigned]
  • CVE Modified by [email protected]

    Jan. 11, 2024

    Action Type Old Value New Value
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JQ5WXFCW2N6G2PH3JXDTYW5PH5EBQEGO/ [No types assigned]
  • CVE Modified by [email protected]

    Jan. 11, 2024

    Action Type Old Value New Value
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRLF5SOS7TP5N7FQSEK2NFNB44ISVTZC/ [No types assigned]
  • Initial Analysis by [email protected]

    Jan. 05, 2024

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
    Changed Reference Type http://www.openwall.com/lists/oss-security/2023/12/24/1 No Types Assigned http://www.openwall.com/lists/oss-security/2023/12/24/1 Mailing List, Third Party Advisory
    Changed Reference Type http://www.openwall.com/lists/oss-security/2023/12/25/1 No Types Assigned http://www.openwall.com/lists/oss-security/2023/12/25/1 Mailing List, Third Party Advisory
    Changed Reference Type https://access.redhat.com/security/cve/CVE-2023-51764 No Types Assigned https://access.redhat.com/security/cve/CVE-2023-51764 Third Party Advisory
    Changed Reference Type https://bugzilla.redhat.com/show_bug.cgi?id=2255563 No Types Assigned https://bugzilla.redhat.com/show_bug.cgi?id=2255563 Issue Tracking, Third Party Advisory
    Changed Reference Type https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html No Types Assigned https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html Technical Description
    Changed Reference Type https://github.com/duy-31/CVE-2023-51764 No Types Assigned https://github.com/duy-31/CVE-2023-51764 Exploit, Third Party Advisory
    Changed Reference Type https://github.com/eeenvik1/CVE-2023-51764 No Types Assigned https://github.com/eeenvik1/CVE-2023-51764 Exploit, Third Party Advisory
    Changed Reference Type https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/ No Types Assigned https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/ Technical Description, Third Party Advisory
    Changed Reference Type https://www.postfix.org/smtp-smuggling.html No Types Assigned https://www.postfix.org/smtp-smuggling.html Exploit, Mitigation, Vendor Advisory
    Changed Reference Type https://www.youtube.com/watch?v=V8KPV96g1To No Types Assigned https://www.youtube.com/watch?v=V8KPV96g1To Exploit
    Added CWE NIST CWE-345
    Added CPE Configuration OR *cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:* versions up to (excluding) 3.5.23 *cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:* versions from (including) 3.6.0 up to (excluding) 3.6.13 *cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:* versions from (including) 3.7.0 up to (excluding) 3.7.9 *cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:* versions from (including) 3.8.0 up to (excluding) 3.8.4
    Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
    Added CPE Configuration OR *cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Jan. 04, 2024

    Action Type Old Value New Value
    Added Reference MITRE https://www.youtube.com/watch?v=V8KPV96g1To [No types assigned]
  • CVE Modified by [email protected]

    Dec. 29, 2023

    Action Type Old Value New Value
    Added Reference MITRE https://github.com/eeenvik1/CVE-2023-51764 [No types assigned]
    Added Reference MITRE https://github.com/duy-31/CVE-2023-51764 [No types assigned]
  • CVE Modified by [email protected]

    Dec. 26, 2023

    Action Type Old Value New Value
    Added Reference MITRE https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html [No types assigned]
  • CVE Modified by [email protected]

    Dec. 26, 2023

    Action Type Old Value New Value
    Changed Description Postfix through 3.8.4 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages that appear to originate from the Postfix server, 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: 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. Postfix through 3.8.4 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: 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.
    Added Reference MITRE http://www.openwall.com/lists/oss-security/2023/12/25/1 [No types assigned]
    Added Reference MITRE https://bugzilla.redhat.com/show_bug.cgi?id=2255563 [No types assigned]
    Added Reference MITRE https://access.redhat.com/security/cve/CVE-2023-51764 [No types assigned]
  • CVE Modified by [email protected]

    Dec. 24, 2023

    Action Type Old Value New Value
    Added Reference MITRE http://www.openwall.com/lists/oss-security/2023/12/24/1 [No types assigned]
  • CVE Received by [email protected]

    Dec. 24, 2023

    Action Type Old Value New Value
    Added Description Postfix through 3.8.4 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages that appear to originate from the Postfix server, 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: 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.
    Added Reference MITRE https://www.postfix.org/smtp-smuggling.html [No types assigned]
    Added Reference MITRE https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/ [No types assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2023-51764 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2023-51764 weaknesses.

CAPEC-111: JSON Hijacking (aka JavaScript Hijacking) JSON Hijacking (aka JavaScript Hijacking) CAPEC-141: Cache Poisoning Cache Poisoning CAPEC-142: DNS Cache Poisoning DNS Cache Poisoning CAPEC-148: Content Spoofing Content Spoofing CAPEC-218: Spoofing of UDDI/ebXML Messages Spoofing of UDDI/ebXML Messages CAPEC-384: Application API Message Manipulation via Man-in-the-Middle Application API Message Manipulation via Man-in-the-Middle CAPEC-385: Transaction or Event Tampering via Application API Manipulation Transaction or Event Tampering via Application API Manipulation CAPEC-386: Application API Navigation Remapping Application API Navigation Remapping CAPEC-387: Navigation Remapping To Propagate Malicious Content Navigation Remapping To Propagate Malicious Content CAPEC-388: Application API Button Hijacking Application API Button Hijacking CAPEC-665: Exploitation of Thunderbolt Protection Flaws Exploitation of Thunderbolt Protection Flaws CAPEC-701: Browser in the Middle (BiTM) Browser in the Middle (BiTM)
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.36 }} 0.06%

score

0.73023

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: