Detection rules › Sublime MQL

Headers: Zimbra mailer from a non-supported OS version

Severity
medium
Type
rule
Source
github.com/sublime-security/sublime-rules

Detects Zimbra originated emails sent from non-supported Windows versions. Observed in widespread HTML credential phishing campaigns.

Event coverage

Message attribute
headers (collection)
type

Rule body MQL

type.inbound
and strings.starts_with(headers.mailer, "Zimbra")
and regex.icontains(headers.mailer, '\b(5\.1|6\.1)\.\d{4}\b')

Detection logic

Scope: inbound message.

Detects Zimbra originated emails sent from non-supported Windows versions. Observed in widespread HTML credential phishing campaigns.

  1. inbound message
  2. headers.mailer starts with 'Zimbra'
  3. headers.mailer matches '\\b(5\\.1|6\\.1)\\.\\d{4}\\b'

Inspects: headers.mailer, type.inbound. Sensors: regex.icontains, strings.starts_with.

Indicators matched (2)

FieldMatchValue
strings.starts_withprefixZimbra
regex.icontainsregex\b(5\.1|6\.1)\.\d{4}\b