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FreeBSDOperating system

CVE-2017-11103

HIGH · 8.1 CVSS v3.1 Published 2017-07-13
Fix available
A fix is available. Upgrade to 4.4.15 / 4.5.12 or later.
See remediation →
90/100
Remediation priority · Urgent
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
Heimdal before 7.4 allows remote attackers to impersonate services with Orpheus' Lyre attacks because it obtains service-principal names in a way that violates the Kerberos 5 protocol specification. In _krb5_extract_ticket() the KDC-REP service name must be obtained from the encrypted version stored in 'enc_part' instead of the unencrypted version stored in 'ticket'. Use of the unencrypted version provides an opportunity for successful server impersonation and other attacks. NOTE: this CVE is only for Heimdal and other products that embed Heimdal code; it does not apply to other instances in which this part of the Kerberos 5 protocol specification is violated.

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

Heimdal Kerberos before 7.4 has a vulnerability in _krb5_extract_ticket() where the KDC-REP service name is obtained from the unencrypted 'ticket' field instead of the encrypted 'enc_part', violating the Kerberos 5 protocol specification. This allows remote attackers to perform Orpheus' Lyre attacks to impersonate services.

MitigationUpgrade to Heimdal 7.4 or later, which properly obtains the service principal name from the encrypted portion of the KDC-REP response.

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
FreeBSDOperating system
Affected:all versions
Debian LinuxOperating system
Affected:= 8.0= 9.0= 10.0
HeimdalApplication
Affected:< 7.4.0
SambaApplication
Affected:>= 4.0.0, < 4.4.15>= 4.5.0, < 4.5.12>= 4.6.0, < 4.6.6
Iphone OsOperating system
Affected:< 11.0
Mac Os XOperating system
Affected:< 10.13.1

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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. Identify if Heimdal Kerberos is installed
    Run 'kinit --version' or check package manager (dpkg -l | grep heimdal, rpm -qa | grep heimdal)
    Affected if Heimdal is installed and version is below 7.4.0
  2. Identify if Samba uses Heimdal backend
    Check Samba version with 'smbd --version' and verify if configured to use Heimdal for Kerberos (look for 'kerberos method' in smb.conf)
    Affected if Samba version is 4.0.0-4.4.14, 4.5.0-4.5.11, or 4.6.0-4.6.5 and uses Heimdal for Kerberos authentication
  3. Verify if Kerberos KDC service is running
    Check for kdc process (ps aux | grep kdc) or check port 88 is listening (netstat -an | grep 88)
    Affected if Kerberos KDC is running with vulnerable Heimdal version
  4. Check FreeBSD Kerberos implementation
    On FreeBSD systems, check if base Kerberos is from Heimdal (klist -V or check /usr/lib/libkrb5.a)
    Affected if FreeBSD version uses Heimdal-based Kerberos and is not patched
  5. Verify Kerberos client usage for service tickets
    Monitor or audit Kerberos ticket requests (klist, audit logs for krb5 functions) to confirm the vulnerable code path is exercised
    Affected if The environment processes KDC-REP responses where service name is extracted from unencrypted ticket

Your environment is affected if you run any Heimdal version below 7.4.0, or Samba versions in the affected ranges using Heimdal, as the KDC-REP service name extraction uses the unencrypted ticket field instead of the encrypted enc_part.

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
Upgrade available Upgrade to 4.4.15 / 4.5.12 / 4.6.6 or later
Fixed in 4.4.154.5.124.6.6
Interim mitigation

Upgrade to Heimdal 7.4 or later, which properly obtains the service principal name from the encrypted portion of the KDC-REP response.

Fix this in FreeBSD Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,928.

Scan for this in your stack

Free · runs locally
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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-2017-11103 in production — separate from our analysis above.

No notes yet

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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