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Web Security ApplianceApplication · Cisco

CVE-2016-9212

HIGH · 7.5 CVSS v3.0 Published 2016-12-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the Decrypt for End-User Notification configuration parameter of Cisco AsyncOS Software for Cisco Web Security Appliances could allow an unauthenticated, remote attacker to connect to a secure website over Secure Sockets Layer (SSL) or Transport Layer Security (TLS), even if the WSA is configured to block connections to the website. Affected Products: This vulnerability affects Cisco Web Security Appliances if the HTTPS decryption options are enabled and configured for the device to block connections to certain websites. More Information: CSCvb49012. Known Affected Releases: 9.0.1-162 9.1.1-074.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in the Decrypt for End-User Notification configuration parameter of Cisco AsyncOS Software for Cisco Web Security Appliances allows an unauthenticated remote attacker to bypass SSL/TLS website blocking controls. When HTTPS decryption is enabled and the WSA is configured to block certain websites, an attacker can still connect to those blocked sites over SSL/TLS due to this configuration bypass.

MitigationApply the relevant Cisco security patch or upgrade to a fixed AsyncOS release. Until patched, consider additional network-level controls or disable HTTPS decryption if operationally feasible while understanding the security tradeoff.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Web Security ApplianceApplication
Affected:= 9.0.1-162= 9.1.1-074

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm device is Cisco Web Security Appliance
    Access the WSA web interface and navigate to System Administration > System Setup > Status, or run CLI command 'show hardware' to verify the appliance model
    Affected if Device is not a Cisco Web Security Appliance - this CVE does not apply
  2. Check AsyncOS version
    Run CLI command 'version' or check via web interface at System Administration > System Setup > Status. Compare your installed version against the affected versions 9.0.1-162 and 9.1.1-074
    Affected if AsyncOS version matches or falls within the affected ranges 9.0.1-162 or 9.1.1-074
  3. Verify HTTPS decryption is enabled
    Check the HTTPS Proxy settings in the WSA web interface under Security Services > HTTPS Proxy, or use CLI command 'httpsconfig' to inspect decryption settings
    Affected if HTTPS decryption is enabled - the vulnerability requires HTTPS decryption to be turned on
  4. Confirm Decrypt for End-User Notification is configured
    Examine the HTTPS decryption policies in the WSA web interface under Web Security Manager > HTTPS Policies, specifically checking if 'Decrypt for End-User Notification' or equivalent end-user notification with decryption is enabled
    Affected if Decrypt for End-User Notification feature is enabled - this is the specific configuration that triggers the bypass
  5. Check for SSL/TLS blocking policies
    Review access policies under Web Security Manager > Access Policies to verify if there are active policies configured to block specific HTTPS/SSL websites
    Affected if Blocking policies for HTTPS/SSL sites are configured - without blocking policies, there is nothing to bypass

Environment is affected if it is a Cisco WSA with AsyncOS version matching 9.0.1-162 or 9.1.1-074, HTTPS decryption enabled, Decrypt for End-User Notification configured, and SSL/TLS blocking policies in place.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the relevant Cisco security patch or upgrade to a fixed AsyncOS release. Until patched, consider additional network-level controls or disable HTTPS decryption if operationally feasible while understanding the security tradeoff.

Fix this in Web Security Appliance Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-9212 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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