Exploit This

Security News, Exploits, and Vulnerabilities.

Microsoft Security Updates April 2015

Microsoft releases 11 Security Bulletins (MS15-032 through MS15-042) today, addressing a list of over 25 CVE-identified vulnerabilities for April of 2015. Critical vulnerabilities are fixed in Internet Explorer, Microsoft Office, and the network and graphics stacks. Most of the critical remote… Read Full Article

Your Tax Refund with a Data Kidnapping Twist!

Knowing that many are on the lookout for emails from the Internal Revenue Service concerning pending refunds, criminals have crafted some of their own.

TA15-103A: DNS Zone Transfer AXFR Requests May Leak Domain Information

Original release date: April 13, 2015

Systems Affected

Misconfigured Domain Name System (DNS) servers that respond to global Asynchronous Transfer Full Range (AXFR) requests.

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.

References

Revision History

  • April 13, 2015: Initial Release

This product is provided subject to this Notification and this Privacy & Use policy.

White Lodging Confirms Second Breach

In February 2015, KrebsOnSecurity reported that for the second time in a year, multiple financial institutions were complaining of fraud on customer credit and debit cards that were all recently used at a string of hotel properties run by hotel franchise firm White Lodging Services Corporation. The company said at the time that it had no evidence of a new breach, but last week White Lodging finally acknowledged a “suspected” breach of point-of-sale systems at 10 locations.

Challenging CoinVault – it’s time to free those files

Some months ago we wrote a blog post about CoinVault. In that post we explained how we tore the malware apart in order to get to its original code and not the obfuscated one.

Simda’s Hide and Seek: Grown-up Games

Kaspersky Lab was recently involved in botnet takedown operation. Preliminary analysis of some of the sinkholed server logs revealed a list of 40 countries affected by the Simda botnet.

Darwin Nuke

In December 2014 we discovered a very interesting vulnerability in the Darwin kernel. Using it attackers can send just one incorrect network packet to the victim and the victim’s system (OS X 10.10 or iOS 8) will crash.

Don’t Be Fodder for China’s ‘Great Cannon’

China has been actively diverting unencrypted Web traffic destined for its top online search service — Baidu.com — so that some visitors from outside of the country were unwittingly enlisted in a novel and unsettling series of denial-of-service attacks aimed at sidelining sites that distribute anti-censorship tools, according to research released this week.

The Banking Trojan Emotet: Detailed Analysis

The Emotet Trojan is a highly automated and developing, territorially-targeted bank threat. Its small size, the dispersal methods used and the modular architecture, all make Emotet a very effective weapon for the cyber-criminal.

TA15-098A: AAEH

Original release date: April 09, 2015

Systems Affected

  • Microsoft Windows 95, 98, Me, 2000, XP, Vista, 7, and 8
  • Microsoft Server 2003, Server 2008, Server 2008 R2, and Server 2012

Overview

AAEH is a family of polymorphic downloaders created with the primary purpose of downloading other malware, including password stealers, rootkits, fake antivirus, and ransomware.

The United States Department of Homeland Security (DHS), in collaboration with Europol, the Federal Bureau of Investigation (FBI) and the Department of Justice (DOJ), released this Technical Alert to provide further information about the AAEH botnet, along with prevention and mitigation recommendations.

Description

AAEH is often propagated across networks, removable drives (USB/CD/DVD), and through ZIP and RAR archive files. Also known as VObfus, VBObfus, Beebone or Changeup, the polymorphic malware has the ability to change its form with every infection. AAEH is a polymorphic downloader with more than 2 million unique samples. Once installed, it morphs every few hours and rapidly spreads across the network.  AAEH has been used to download other malware families, such as Zeus, Cryptolocker, ZeroAccess, and Cutwail.

Impact

A system infected with AAEH may be employed to distribute malicious software, harvest users’ credentials for online services, including banking services, and extort money from users by encrypting key files and then demanding payment in order to return the files to a readable state. AAEH is capable of defeating anti-virus products by blocking connections to IP addresses associated with Internet security companies and by preventing anti-virus tools from running on infected machines.  

Solution

Users are recommended to take the following actions to remediate AAEH infections:

  • Use and maintain anti-virus software – Anti-virus software recognizes and protects your computer against most known viruses. It is important to keep your anti-virus software up-to-date (see Understanding Anti-Virus Software for more information).
  • Change your passwords – Your original passwords may have been compromised during the infection, so you should change them (see Choosing and Protecting Passwords for more information).
  • Keep your operating system and application software up-to-date – Install software patches so that attackers can’t take advantage of known problems or vulnerabilities. Many operating systems offer automatic updates. If this option is available, you should enable it (see Understanding Patches for more information).
  • Use anti-malware tools – Using a legitimate program that identifies and removes malware can help eliminate an infection.

Users can consider employing a remediation tool (examples below) that will help with the removal of AAEH from your system.

Note: AAEH blocks AV domain names thereby preventing infected users from being able to download remediation tools directly from an AV company. The links below will take you to the tools at the respective AV sites. In the event that the tools cannot be accessed or downloaded from the vendor site, the tools are accessible from Shadowserver (http://aaeh.shadowserver.org).

The below are examples only and do not constitute an exhaustive list. The U.S. Government does not endorse or support any particular product or vendor.

References

Revision History

  • April 9, 2015: Initial Release

This product is provided subject to this Notification and this Privacy & Use policy.

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