Email spoofing via permissive DATA termination
Published Mar 11, 2024 · Updated Aug 27, 2024
SMTP smuggling in Postal before 3.0.0 allows remote attackers to spoof incoming email through a cooperative outgoing SMTP service. The SMTP server's DATA handler accepts a lone dot after non-RFC line endings as an end-of-data marker, enabling appended SMTP commands to become a second message. Exploitation requires an outgoing SMTP service that preserves the crafted delimiter; successful mail can appear to originate from an authorized sender.
Summary
What happened
SMTP smuggling in Postal before 3.0.0 allows remote attackers to spoof incoming email through a cooperative outgoing SMTP service. The SMTP server's DATA handler accepts a lone dot after non-RFC line endings as an end-of-data marker, enabling appended SMTP commands to become a second message. Exploitation requires an outgoing SMTP service that preserves the crafted delimiter; successful mail can appear to originate from an authorized sender.
The record
- CVE
- CVE-2024-27938
- Published
- Mar 11, 2024
- Updated
- Aug 27, 2024
- Vendor
- Postal
- Product
- Postal
- Classifications
- CWE-116, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 11, 2024CVE publishedPublication date reported by the CVE source.
- Aug 27, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <3.0.0
- Affected versionversion=< 3.0.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- SMTP Smuggling Scannerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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