CVE-2019-5456 — SMTP MITM refers to a malicious actor setting up an SMTP proxy server between th

SMTP MITM refers to a malicious actor setting up an SMTP proxy server between the UniFi Controller version <= 5.10.21 and their actual SMTP server to record their SMTP credentials for malicious use later.

01What is this vulnerability?

SMTP MITM refers to a malicious actor setting up an SMTP proxy server between the UniFi Controller version <= 5.10.21 and their actual SMTP server to record their SMTP credentials for malicious use later.

02Affected products

Vendor	Product	Versions
UniFi	UniFi	<= 5.10.21

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-07-30T20:19:48.000Z
• Last modified: 2024-08-04T19:54:53.544Z

09References

• hackerone.com — https://hackerone.com/reports/519582
• community.ui.com — https://community.ui.com/releases/Security-Advisory-Bulletin-003-003/982bbaa8-2a…
• community.ui.com — https://community.ui.com/releases/862b962b-55f6-4324-96be-610f647d5c1c
• community.ui.com — https://community.ui.com/releases/9f698d0b-8279-40d3-9f1a-d36db4813124