Big Ip Local Traffic ManagerApplication · F5

CVE-2017-6163

MEDIUM · 5.9 CVSS v3.0 Published 2017-10-27

Fix available

A fix is available. Upgrade to after 11.5.4 or later.

See remediation →

68/100

Remediation priority · Elevated

Remotely reachable No privileges Zero-click

Official description

NVD · unedited

In F5 BIG-IP LTM, AAM, AFM, APM, ASM, Link Controller, PEM, PSM software version 12.0.0 to 12.1.2, 11.6.0 to 11.6.1, 11.4.0 to 11.5.4, when a virtual server uses the standard configuration of HTTP/2 or SPDY profile with Client SSL profile, and the client initiates a number of concurrent streams beyond the advertised limit can cause a disruption of service. Remote client initiating stream beyond the advertised limit can cause a disruption of service. The Traffic Management Microkernel (TMM) data plane is exposed to this issue; the control plane is not exposed.

Technical summary

dbcve analysis · high confidence

F5 BIG-IP devices with HTTP/2 or SPDY profiles combined with Client SSL profiles fail to properly enforce stream concurrency limits. When clients initiate concurrent streams exceeding the advertised limit, it causes disruption of the TMM (Traffic Management Microkernel) data plane, resulting in denial of service.

MitigationUpgrade F5 BIG-IP to a fixed version (13.0.0+ or later 12.x/11.x patches per K05113982) that properly enforces HTTP/2 stream limits. Alternatively, disable HTTP/2/SPDY profiles if not required.

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

Affected products & versions

NVD · CPE data

Big Ip Local Traffic ManagerApplication

Affected:>= 11.4.0, <= 11.5.3= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

Big Ip Application Acceleration ManagerApplication

Affected:>= 11.4.0, <= 11.5.4= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

Big Ip Advanced Firewall ManagerApplication

Affected:>= 11.4.0, <= 11.5.4= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

Big Ip Access Policy ManagerApplication

Affected:>= 11.5.0, <= 11.5.4= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

Big Ip Application Security ManagerApplication

Affected:>= 11.5.0, <= 11.5.4= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

Big Ip Link ControllerApplication

Affected:>= 11.5.0, <= 11.5.4= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

Big Ip Policy Enforcement ManagerApplication

Affected:>= 11.5.0, <= 11.5.4= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

Big Ip Protocol Security ModulePlugin / extension

Affected:> 11.4.0, <= 11.5.4= 11.6.0= 11.6.1= 12.0.0= 12.1.0= 12.1.1= 12.1.2

CVSS breakdown

From the vector

Attack vector: Network
Complexity: High
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Am I affected?

dbcve checks

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

Identify the installed BIG-IP version

Run `tmsh show sys version` or check the BIG-IP GUI under System > Software Management > Install ISO to confirm the running version number

Affected if The version matches any of these: 11.4.0-11.5.3, 11.6.0-11.6.1, 12.0.0-12.1.2 (all 11.5.4+ versions in the 11.x line are NOT affected except 11.6.0 and 11.6.1)
Locate HTTP/2 profiles

In the BIG-IP GUI, go to Local Traffic > Profiles > HTTP/2, or run `tmsh list ltm profile http2` to list all HTTP/2 profiles configured on the device

Affected if Any HTTP/2 profile exists on the device (even if not assigned to a virtual server, the presence matters for attack surface)
Locate SPDY profiles

In the BIG-IP GUI, go to Local Traffic > Profiles > SPDY, or run `tmsh list ltm profile spdy` to list all SPDY profiles configured on the device

Affected if Any SPDY profile exists on the device
Verify Client SSL profiles are combined with HTTP/2 or SPDY

For each virtual server, check if it references both a Client SSL profile and an HTTP/2 or SPDY profile. Run `tmsh list ltm virtual` and inspect the 'profile' section for combinations of clientSsl and http2 or spdy profiles

Affected if A virtual server has both a Client SSL profile and an HTTP/2 or SPDY profile assigned to it simultaneously
Confirm stream concurrency settings

Examine the HTTP/2 or SPDY profile settings for the 'Concurrent Streams Per Connection' or equivalent limit setting by running `tmsh list ltm profile http2 <profile_name>` or `tmsh list ltm profile spdy <profile_name>`

Affected if A limit is set but may not be properly enforced (this is the vulnerable condition - the flaw is in enforcement, not configuration)

The device is vulnerable if it runs an affected version (11.4.0-11.5.3, 11.6.0, 11.6.1, or 12.0.0-12.1.2) AND has a virtual server with both an HTTP/2 or SPDY profile combined with a Client SSL profile.

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

Remediation

From vendor data

Upgrade available Upgrade to a release after 11.5.4

Interim mitigation

Upgrade F5 BIG-IP to a fixed version (13.0.0+ or later 12.x/11.x patches per K05113982) that properly enforces HTTP/2 stream limits. Alternatively, disable HTTP/2/SPDY profiles if not required.

Fix this in Big Ip Local Traffic Manager Scoped from the published advisory

Consultation4.0 h
Implementation8.0 h
Testing4.0 h
Review / QA2.0 h

18.0 hours of engineering $3,200

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References

Primary sources

support.f5.comVendor Advisory
www.securityfocus.comThird Party AdvisoryVDB Entry
www.securitytracker.comThird Party AdvisoryVDB Entry
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-6163 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2017-6163?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsUpgrade to after 11.5.4 or later

Severity 5.9 Medium

Exploit likelihood EPSS, next 30 days 1.7%

Affects: Big Ip Local Traffic Manager

Remediation

Need this fixed?

Fix this in Big Ip Local Traffic Manager 18 hrs · Moderate

Typical engagement from $3,200

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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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References