Vulnerability Details : CVE-2023-51764
Potential exploit
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.
Products affected by CVE-2023-51764
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
- cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
- cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:*
- cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:*
- cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:*
- cpe:2.3:a:postfix:postfix:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2023-51764
33.24%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 97 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2023-51764
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
5.3
|
MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
3.9
|
1.4
|
NIST | 2024-01-05 |
CWE ids for CVE-2023-51764
-
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.Assigned by: nvd@nist.gov (Primary)
References for CVE-2023-51764
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https://github.com/duy-31/CVE-2023-51764
GitHub - duy-31/CVE-2023-51764: Postfix SMTP Smuggling - Expect Script POCExploit;Third Party Advisory
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https://bugzilla.redhat.com/show_bug.cgi?id=2255563
2255563 – (CVE-2023-51764) CVE-2023-51764 postfix: SMTP smuggling vulnerabilityIssue Tracking;Third Party Advisory
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http://www.openwall.com/lists/oss-security/2023/12/24/1
oss-security - Re: Re: New SMTP smuggling attackMailing List;Third Party Advisory
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https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.html
Lecture: SMTP Smuggling – Spoofing E-Mails Worldwide | Wednesday | Schedule 37th Chaos Communication CongressTechnical Description
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https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/
SMTP Smuggling - Spoofing E-Mails Worldwide - SEC ConsultTechnical Description;Third Party Advisory
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https://access.redhat.com/security/cve/CVE-2023-51764
CVE-2023-51764- Red Hat Customer PortalThird Party Advisory
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https://lwn.net/Articles/956533/
Smuggling email inside of email [LWN.net]
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https://www.youtube.com/watch?v=V8KPV96g1To
37C3 - SMTP Smuggling – Spoofing E-Mails Worldwide - YouTubeExploit
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https://www.openwall.com/lists/oss-security/2024/01/22/1
oss-security - Postfix updated SMTP smuggling countermeasure
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https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JQ5WXFCW2N6G2PH3JXDTYW5PH5EBQEGO/
[SECURITY] Fedora 38 Update: postfix-3.7.9-1.fc38 - package-announce - Fedora Mailing-Lists
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http://www.openwall.com/lists/oss-security/2024/05/09/3
oss-security - Re: New SMTP smuggling attack
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https://github.com/eeenvik1/CVE-2023-51764
GitHub - eeenvik1/CVE-2023-51764: PoC CVE-2023-51764Exploit;Third Party Advisory
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http://www.openwall.com/lists/oss-security/2023/12/25/1
oss-security - Re: Re: New SMTP smuggling attackMailing List;Third Party Advisory
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https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRLF5SOS7TP5N7FQSEK2NFNB44ISVTZC/
[SECURITY] Fedora 39 Update: postfix-3.8.4-1.fc39 - package-announce - Fedora Mailing-Lists
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https://www.postfix.org/announcements/postfix-3.8.5.html
Postfix stable release 3.8.5, 3.7.10, 3.6.14, 3.5.24
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https://www.postfix.org/smtp-smuggling.html
SMTP SmugglingExploit;Mitigation;Vendor Advisory
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https://lists.debian.org/debian-lts-announce/2024/01/msg00020.html
[SECURITY] [DLA 3725-1] postfix security update
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