Posts Tagged: threatexpert

Jan 14

New Clues in the Target Breach

An examination of the malware used in the Target breach suggests that the attackers may have had help from a poorly secured feature built into a widely-used IT management software product that was running on the retailer’s internal network.

As I noted in  Jan. 15’s story — A First Look at the Target Intrusion, Malware — the attackers were able to infect Target’s point-of-sale registers with a malware strain that stole credit and debit card data. The intruders also set up a control server within Target’s internal network that served as a central repository for data hoovered up from all of the infected registers.

According to sources, "ttcopscli3acs" is the name of the Windows share point used by the POS malware planted at Target stores; the username that the thieves used to log in remotely and download stolen card data was "Best1_user"; the password was "BackupU$r"

“ttcopscli3acs” is the name of the Windows share used by the POS malware planted at Target stores; the username that malware used to upload stolen card data was “Best1_user”; the password was “BackupU$r”

That analysis looked at a malware component used in Target breach that was uploaded to Symantec’s ThreatExpert scanning service on Dec. 18 but which was later deleted (a local PDF copy of it is here). The ThreatExpert writeup suggests that the malware was responsible for moving stolen data from the compromised cash registers to that shared central repository, which had the internal address of The “ttcopscli3acs” bit is the Windows domain name used on Target’s network. The user account “Best1_user” and password “BackupU$r” were used to log in to the shared drive (indicated by the “S:” under the “Resource Type” heading in the image above.

That “Best1_user” account name seems an odd one for the attackers to have picked at random, but there is a better explanation: That username is the same one that gets installed with an IT management software suite called Performance Assurance for Microsoft Servers. This product, according to its maker — Houston, Texas base BMC Software — includes administrator-level user account called “Best1_user.”

This knowledge base article (PDF) published by BMC explains the Best1_user account is installed by the software to do routine tasks. That article states that while the Best1_user account is essentially a “system” or “administrator” level account on the host machine, customers shouldn’t concern themselves with this account because “it is not a member of any group (not even the ‘users’ group) and therefore can’t be used to login to the system.”

“The only privilege that the account is granted is the ability to run as a batch job,” the document states, indicating that it could be used to run programs if invoked from a command prompt. Here’s my favorite part:

Perform Technical Support does not have the password to this account and this password has not be released by Perform Development. Knowing the password to the account should not be important as you cannot log into the machine using this account. The password is known internally and used internally by the Perform agent to assume the identity of the “Best1_user” account.”

I pinged BMC to find out if perhaps the password supplied in the Target malware (BackupU$r) is in fact the secret password for the Best1_user account. The company has so far remained silent on this question.

This was the hunch put forward by the Counter Threat Unit (CTU) of Dell SecureWorks in an analysis that was privately released to some of the company’s clients this week.

Relationships between compromised and attacker-controlled assets. Source: Dell Secureworks.

Relationships between compromised and attacker-controlled assets. Source: Dell Secureworks.

“Attackers exfiltrate data by creating a mount point for a remote file share and copying the data stored by the memory-scraping component to that share,” the SecureWorks paper notes. “In the previous listing showing the data’s move to an internal server, is the intermediate server selected by attackers, and CTU researchers believe the “ttcopscli3acs” string is the Windows domain name used on Target’s network. The Best1_user account appears to be associated with the Performance Assurance component of BMC Software’s Patrol product. According to BMC’s documentation, this account is normally restricted, but the attackers may have usurped control to facilitate lateral movement within the network.

According to SecureWorks, one component of the malware installed itself as a service called “BladeLogic,” a service name no doubt designed to mimic another BMC product called BMC BladeLogic Automation Suite. BMC spokeswoman Ann Duhon said that the attackers were simply invoking BMC’s trademark to make the malicious program appear legitimate to the casual observer, but it seems likely that at least some BMC software was running inside of Target’s network, and that the attackers were well aware of it.

Update Jan. 30, 5:48 p.m.: BMC just issued the following statement:

There have been several articles in the press speculating about the Target breach.  BMC Software has received no information from Target or the investigators regarding the breach. In some of those articles, BMC products were mentioned in two different ways.

The first was a mention of a “bladelogic.exe” reference in the attack.   The executable name “bladelogic.exe” does not exist in any piece of legitimate BMC software.  McAfee has issued a security advisory stating that: “The reference to “bladelogic” is a method of obfuscation.  The malware does not compromise, or integrate with, any BMC products in any way.

The second reference was to a password that was possibly utilized as part of the attack, with the implication that it was a BMC password.  BMC has confirmed that the password mentioned in the press is not a BMC-generated password.

At this point, there is nothing to suggest that BMC BladeLogic or BMC Performance Assurance has a security flaw or was compromised as part of this attack.

Malware is a problem for all IT environments. BMC asks all of our customers to be diligent in ensuring that their environments are secure and protected.

I parse their statement to mean that the “BackupU$r” password referenced in the Target malware is not their software’s secret password. But nothing in the statement seems to rule out the possibility that the attackers leveraged a domain user account installed by BMC software to help exfiltrate card data from Target’s network.

Original story:

According to a trusted source who uses mostly open-source data to keep tabs on the software and hardware used in various retail environments, BMC’s software is in use at many major retail and grocery chains across the country, including Kroger, Safeway, Home Depot, Sam’s Club and The Vons Companies, among many others.

A copy of the SecureWorks report is here (PDF). It contains some fairly detailed analysis of this and other portions of the malware used in the Target intrusion. What it states up front that it does not have — and what we still have not heard from Target — is how the attackers broke in to begin with….

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Jan 14

A First Look at the Target Intrusion, Malware

Last weekend, Target finally disclosed at least one cause of the massive data breach that exposed personal and financial information on more than 110 million customers: Malicious software that infected point-of-sale systems at Target checkout counters. Today’s post includes new information about the malware apparently used in the attack, according to two sources with knowledge of the matter.

The seller of the point-of-sale "memory dump" malware used in the Target attack.

The seller of the point-of-sale “memory dump” malware allegedly used in the Target attack.

In an interview with CNBC on Jan. 12, Target CEO Gregg Steinhafel confirmed that the attackers stole card data by installing malicious software on point-of-sale (POS) devices in the checkout lines at Target stores. A report published by Reuters that same day stated that the Target breach involved memory-scraping malware.

This type of malicious software uses a technique that parses data stored briefly in the memory banks of specific POS devices; in doing so, the malware captures the data stored on the card’s magnetic stripe in the instant after it has been swiped at the terminal and is still in the system’s memory. Armed with this information, thieves can create cloned copies of the cards and use them to shop in stores for high-priced merchandise. Earlier this month, U.S. Cert issued a detailed analysis of several common memory scraping malware variants.

Target hasn’t officially released details about the POS malware involved, nor has it said exactly how the bad guys broke into their network. Since the breach, however, at least two sources with knowledge of the ongoing investigation have independently shared information about the point-of-sale malware and some of the methods allegedly used in the attack.


On Dec. 18, three days after Target became aware of the breach and the same day this blog broke the story, someone uploaded a copy of the point-of-sale malware used in the Target breach to, a malware scanning service owned by security firm Symantec. The report generated by that scan was very recently removed, but it remains available via Google cache (Update, Jan. 16, 9:29 a.m.: Sometime after this story ran, Google removed the cached ThreatExpert report; I’ve uploaded a PDF version of it here).

According to sources, "ttcopscli3acs" is the name of the Windows share point used by the POS malware planted at Target stores; the username that the thieves used to log in remotely and download stolen card data was "Best1_user"; the password was "BackupU$r"

According to sources, “ttcopscli3acs” is the name of the Windows computer name/domain used by the POS malware planted at Target stores; the username that the malware used to upload stolen data data was “Best1_user”; the password was “BackupU$r”

According to a source close to the investigation, that report is related to the malware analyzed at this Symantec writeup (also published Dec. 18) for a point-of-sale malware strain that Symantec calls “Reedum” (note the Windows service name of the malicious process is the same as the ThreatExpert analysis –“POSWDS”). Interestingly, a search in — a Google-owned malware scanning service — for the term “reedum” suggests that this malware has been used in previous intrusions dating back to at least June 2013; in the screen shot below left, we can see a notation added to that virustotal submission, “30503 POS malware from FBI”.

The source close to the Target investigation said that at the time this POS malware was installed in Target’s environment (sometime prior to Nov. 27, 2013), none of the 40-plus commercial antivirus tools used to scan malware at flagged the POS malware (or any related hacking tools that were used in the intrusion) as malicious. “They were customized to avoid detection and for use in specific environments,” the source said.

pos-fbiThat source and one other involved in the investigation who also asked not to be named said the POS malware appears to be nearly identical to a piece of code sold on cybercrime forums called BlackPOS, a relatively crude but effective crimeware product. BlackPOS is a specialized piece of malware designed to be installed on POS devices and record all data from credit and debit cards swiped through the infected system.

According the author of BlackPOS — an individual who uses a variety of nicknames, including “Antikiller” — the POS malware is roughly 207 kilobytes in size and is designed to bypass firewall software. The barebones “budget version” of the crimeware costs $1,800, while a more feature-rich “full version” — including options for encrypting stolen data, for example — runs $2,300.

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May 12

Adware Stages Comeback Via Browser Extensions

The Wikimedia Foundation last week warned that readers who are seeing ads on Wikipedia articles are likely using a Web browser that has been infected with malware. The warning points to an apparent resurgence in adware and spyware that is being delivered via cleverly disguised browser extensions designed to run across multiple Web browsers and operating systems.

An ad served by IWantThis! browser extension. Source: Wikimedia

In a posting on its blog, Wikimedia noted that although the nonprofit organization is funded by more than a million donors and does not run ads, some users were complaining of seeing ads on Wikipedia entries. “If you’re seeing advertisements for a for-profit industry (see screenshot below for an example) or anything but our fundraiser, then your web browser has likely been infected with malware,” reads a blog post co-written by Philippe Beaudette, director of community advocacy at the Wikimedia Foundation.

The blog post named one example of a browser extension called “IWantThis!,” which is essentially spyware masquerading as adware. The description at the IWantThis! Web site makes it sound like a harmless plugin that occasionally overlays ads on third-party Web sites and helps users share product or online shopping wish lists with others. As I was researching this extension, I came across this helpful description of it at the DeleteMalware Blog, which points to the broad privacy policy that ships with this extension:

Examples of the information we may collect and analyze when you use our website include the IP address used to connect your computer to the Internet; login; e-mail address; password; computer and connection information such as browser type, version, and time zone setting, browser plug-in types and versions, operating system, and platform; the full Uniform Resource Locator (URL) clickstream to, through, and from the Site, including date and time; cookie; web pages you viewed or searched for; and the phone number you used to call us. Continue reading →

Mar 10

AVprofit: Rogue AV + Zeus = $

The presence of rogue anti-virus products, also known as scareware, on a Microsoft Windows computer is often just the most visible symptom of a more serious and insidious system-wide infection. To understand why, it helps to take a peek inside some of the more popular rogue anti-virus distribution networks that are paying people to peddle scareware alongside far more invasive threats.

Distributors or “affiliates” who sign up with, for example, are given access to an installer program that downloads not only rogue anti-virus but also ZeuS, a stealthy piece of malware that specializes in mining online banking credentials from infected PCs. ZeuS is the very piece of malware directly responsible for helping thieves steal tens of millions of dollars from small to mid-sized businesses over the past year.

Avprofit says it will pay affiliates roughly $1,000 for every 1,000 times they distribute this installer program, or about $1 per install. Typically, affiliates will embed these installers at porn sites or bundle them with programs seeded on peer-to-peer file-sharing services. The nightmare for the victim starts when he or she responds to the fake anti-virus pop-up warning of supposed threats resident on the victim’s PC, by agreeing to download and run a scanning tool.

What’s remarkable about this entire ecosystem is that in many cases, victims who have this installer run on their systems often end up paying for the rogue anti-virus, in addition to unknowingly giving up their passwords and handing complete control of their computer to the bad guys running this distribution network.

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