Detection rules › Sublime MQL

CVE-2023-5631 - Roundcube Webmail XSS via crafted SVG

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

Body HTML contains an exploit for CVE-2023-5631, a vulnerability in Roundcube Webmail that allows stored XSS via an HTML e-mail message with a crafted SVG document.

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

CategoryValues
Attack typesMalware/Ransomware
Tactics and techniquesEvasion, Exploit, HTML smuggling, Scripting

Event coverage

Message attribute
body.html
type

Rule body MQL

type.inbound
and length(attachments) == 0
and strings.ilike(body.html.raw,
                  '*use href="data:image/svg+xml;base64,PHN2Zy*#*'
)

Detection logic

Scope: inbound message.

Body HTML contains an exploit for CVE-2023-5631, a vulnerability in Roundcube Webmail that allows stored XSS via an HTML e-mail message with a crafted SVG document.

  1. inbound message
  2. length(attachments) is 0
  3. body.html.raw matches '*use href="data:image/svg+xml;base64,PHN2Zy*#*'

Inspects: body.html.raw, type.inbound. Sensors: strings.ilike.

Indicators matched (1)

FieldMatchValue
strings.ilikesubstring*use href="data:image/svg+xml;base64,PHN2Zy*#*