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SambaApplication

CVE-2015-3223

MEDIUM · 5.3 CVSS v3.0 Published 2015-12-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
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
The ldb_wildcard_compare function in ldb_match.c in ldb before 1.1.24, as used in the AD LDAP server in Samba 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3, mishandles certain zero values, which allows remote attackers to cause a denial of service (infinite loop) via crafted packets.

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

The ldb_wildcard_compare function in ldb_match.c (used by Samba's AD LDAP server) before version 1.1.24 mishandles zero values, causing an infinite loop when processing specially crafted packets. This leads to denial of service as the affected LDAP server becomes unresponsive.

MitigationUpdate ldb to version 1.1.24 or later, or update affected Samba installations to 4.1.22, 4.2.7, 4.3.3 or later. In the meantime, consider network-level filtering to limit exposure to untrusted LDAP sources.

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
SambaApplication
Affected:= 4.0.0= 4.0.1= 4.0.2= 4.0.3= 4.0.4= 4.0.5= 4.0.6= 4.0.7= 4.0.8= 4.0.9= 4.0.10= 4.0.11

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
None
Availability
Low

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

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. Check installed Samba version
    Run 'samba --version' or 'smbd --version' to display the installed Samba version. On Linux systems, you can also run 'rpm -q samba' or 'dpkg -l samba' to see the package version.
    Affected if The version is 4.0.0 through 4.0.11 (inclusive)
  2. Verify Samba AD DC role is active
    Run 'samba-tool domain info 127.0.0.1' or check if smbd is running with '--option=serverrole=active directory domain controller' to confirm Samba is operating as an AD Domain Controller.
    Affected if Samba is configured and running as an Active Directory Domain Controller (AD DC)
  3. Check ldb library version
    Run 'ldbd --version' or check the ldb package version with 'rpm -q ldb' or 'dpkg -l ldb'. The vulnerable function is in the ldb library used by Samba's LDAP server.
    Affected if The ldb library version is earlier than 1.1.24 and Samba AD DC is running
  4. Identify exposed LDAP service
    Check if TCP port 389 (LDAP) or port 636 (LDAPS) is open and listening on the Samba server using 'netstat -tlnp | grep -E "389|636"' or 'ss -tlnp | grep -E "389|636"'.
    Affected if The LDAP ports are open and exposed, particularly to untrusted networks

You are affected if Samba version 4.0.0-4.0.11 is running as an AD Domain Controller and the LDAP service is exposed, since the vulnerable ldb_wildcard_compare function in this configuration can be triggered by specially crafted packets causing an infinite loop.

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

Update ldb to version 1.1.24 or later, or update affected Samba installations to 4.1.22, 4.2.7, 4.3.3 or later. In the meantime, consider network-level filtering to limit exposure to untrusted LDAP sources.

Fix this in Samba Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
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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-2015-3223 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