Executive Summary

Informations
Name TA15-103A First vendor Publication 2015-04-13
Vendor US-CERT Last vendor Modification 2015-04-13
Severity (Vendor) N/A Revision N/A

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
 
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Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:L/Au:N/C:N/I:N/A:N)
Cvss Base Score 0 Attack Range Network
Cvss Impact Score 0 Attack Complexity Low
Cvss Expoit Score 10 Authentication None Required
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Detail

Overview

A remote unauthenticated user may request a DNS zone transfer from a public-facing DNS server. If improperly configured, the DNS server may respond with information about the requested zone, revealing internal network structure and potentially sensitive information.


Description


AXFR is a protocol for “zone transfers” for replication of DNS data across multiple DNS servers. Unlike normal DNS queries that require the user to know some DNS information ahead of time, AXFR queries reveal subdomain names [1]. Because a zone transfer is a single query, it could be used by an adversary to efficiently obtain DNS data.  


A well-known problem with DNS is that zone transfer requests can disclose domain information; for example, see CVE-1999-0532 and a 2002 CERT/CC white paper [2][3]. However, the issue has regained attention due to recent Internet scans still showing a large number of misconfigured DNS servers. Open-source, tested scripts are now available to scan for the possible exposure, increasing the likelihood of exploitation [4].


Impact


A remote unauthenticated user may observe internal network structure, learning information useful for other directed attacks.


Solution


Configure your DNS server to respond only to zone transfer (AXFR) requests from known IP addresses. Many open-source resources give instructions on reconfiguring your DNS server. For example, see this AXFR article for information on testing and fixing the configuration of a BIND DNS server. US-CERT does not endorse or support any particular product or vendor.


Original Source

Url : http://www.us-cert.gov/cas/techalerts/TA15-103A.html

SAINT Exploits

Description Link
DNS zone transfer More info here

OpenVAS Exploits

Date Description
2005-11-03 Name : DNS AXFR
File : nvt/dns_xfer.nasl

Open Source Vulnerability Database (OSVDB)

Id Description
492 DNS Zone Transfer Information Disclosure

DNS contains a flaw that may lead to an unauthorized information disclosure. The issue is triggered when the host's DNS name server allows zone transfers to replicate zone information between master and slave DNS servers. If zone transfers have not been restricted to authorized slave servers only, a remote attacker could disclose sensitive network information resulting in a loss of confidentiality.

Snort® IPS/IDS

Date Description
2014-01-10 dns zone transfer via TCP detected
RuleID : 255-community - Revision : 24 - Type : PROTOCOL-DNS
2014-01-10 dns zone transfer via UDP detected
RuleID : 1948-community - Revision : 20 - Type : PROTOCOL-DNS
2014-01-10 dns zone transfer via UDP detected
RuleID : 1948 - Revision : 20 - Type : PROTOCOL-DNS

Nessus® Vulnerability Scanner

Date Description
2001-01-16 Name : The remote name server allows zone transfers
File : dns_xfer.nasl - Type : ACT_GATHER_INFO

Alert History

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0
Date Informations
2015-04-14 05:25:19
  • First insertion