Reliance on Reverse DNS Resolution for a Security-Critical Action

Opis

The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.

Since DNS names can be easily spoofed or misreported, and it may be difficult for the product to detect if a trusted DNS server has been compromised, DNS names do not constitute a valid authentication mechanism.

When the product performs a reverse DNS resolution for an IP address, if an attacker controls the DNS server for that IP address, then the attacker can cause the server to return an arbitrary hostname. As a result, the attacker may be able to bypass authentication, cause the wrong hostname to be recorded in log files to hide activities, or perform other attacks.

Attackers can spoof DNS names by either (1) compromising a DNS server and modifying its records (sometimes called DNS cache poisoning), or (2) having legitimate control over a DNS server associated with their IP address.

Skutki

• Access Control

  Gain Privileges or Assume Identity; Bypass Protection Mechanism

  Malicious users can fake authentication information by providing false DNS information.

Zapobieganie

• Architecture and Design

  Use other means of identity verification that cannot be simply spoofed. Possibilities include a username/password or certificate.

• Implementation

  Perform proper forward and reverse DNS lookups to detect DNS spoofing.

Przykłady podatności

• CVE-2001-1488 Does not do double-reverse lookup to prevent DNS spoofing.
• CVE-2001-1500 Does not verify reverse-resolved hostnames in DNS.
• CVE-2000-1221 Authentication bypass using spoofed reverse-resolved DNS hostnames.
• CVE-2002-0804 Authentication bypass using spoofed reverse-resolved DNS hostnames.
• CVE-2001-1155 Filter does not properly check the result of a reverse DNS lookup, which could allow remote attackers to bypass intended access restrictions via DNS spoofing.
• CVE-2004-0892 Reverse DNS lookup used to spoof trusted content in intermediary.
• CVE-2003-0981 Product records the reverse DNS name of a visitor in the logs, allowing spoofing and resultant XSS.

Słabość nadrzędna

• CWE-290 Authentication Bypass by Spoofing
• CWE-807 Reliance on Untrusted Inputs in a Security Decision

Może prowadzić do

• CWE-923 Improper Restriction of Communication Channel to Intended Endpoints

Kiedy powstaje

• Architecture and Design

Dotyczy

Not Language-Specific

Uwagi

CWE-350, CWE-247, and CWE-292 were merged into CWE-350 in CWE 2.5. CWE-247 was originally derived from Seven Pernicious Kingdoms, CWE-350 from PLOVER, and CWE-292 from CLASP. All taxonomies focused closely on the use of reverse DNS for authentication of incoming requests.

Źródła

1. The CLASP Application Security Process — Secure Software, Inc., 2005
2. 24 Deadly Sins of Software Security — Michael Howard, David LeBlanc, John Viega, "Sin 15: Not Updating Easily." Page 231, McGraw-Hill, 2010
3. 24 Deadly Sins of Software Security — Michael Howard, David LeBlanc, John Viega, "Sin 24: Trusting Network Name Resolution." Page 361, McGraw-Hill, 2010
4. The Art of Software Security Assessment — Mark Dowd, John McDonald, Justin Schuh, Chapter 16, "DNS Spoofing", Page 1002, Addison Wesley, 2006