The Vjw0rm Malware Does It All. Here’s What to Watch For.

CISO Summary 

It’s called the Vengeance Justice Worm (Vjw0rm), but think of it as the Leatherman tool of malware. Vjw0rm wreaks havoc in highly versatile ways: information theft, denial of service (DoS) attacks, and self-propagation to name a few. CofenseTM has spotted this hybrid threat—a cross between a worm and a remote access trojan (RAT)—in a recent phishing campaign dangling a banking lure.   

In 2018, Cheap and Easy Malware Flooded Corporate Inboxes

CISO Summary

Sometimes it’s the simple things that make life hard. In 2018, over 2/3 of unique malware campaigns Cofense IntelligenceTM observed were simple, inexpensive “stealers” or remote access trojans (RATs). With exceptionally low barrier-to-entry—an email account or website can handle distribution and communication—these malware types make data theft a viable career choice for threat actors without the skills to use more advanced varieties.

Domain Fronting, Phishing Attacks, and What CISOs Need to Know

CISO Summary

Cofense IntelligenceTM is seeing continued use of a cyber-attack technique known as domain fronting. It’s yet another way hackers conceal their malicious activity, in this case using work-arounds to evade security controls and gain access to command-and-control (C2) infrastructure (scroll down for a technical explanation).

Cozy Bear, the Russian threat actors, used similar tactics when they hacked the Democratic National Committee in 2016. Today, businesses are dealing with phishing and malware attacks that domain fronting enables.

While Google and Amazon have taken measures in their CDNs to curtail this trend, we have seen an uptick in C2 infrastructure hosted in Cloudflare CDNs (figures 2-4 below). Last month, Cofense Intelligence reported that Cloudflare domains were being abused by threat actors to launch malware attacks on finance departments.

Why is this a problem?

If part of your cyber defense strategy is using a web gateway to prevent employees from visiting non-categorized sites, or blocking based on a threat intelligence feed of known C2 hosts, you can’t practically block access to a CDN without disrupting Internet-reliant business processes.

CISOs should make sure their SOCs are aware of the problem when reviewing suspicious emails reported by employees. While we wait for traditional cyber perimeter controls to catch up to this threat, a phishing training and reporting program (see Cofense PhishMeTM and Cofense ReporterTM), plus a phishing-specific response capability (see Cofense TriageTM and Cofense VisionTM) is the last line of defense.

Full Details

Malware operators continue to use domain fronting to bypass security measures and reach their command and control (C2) infrastructure hosted on content delivery networks (CDN). This C2 communication technique is difficult to defend against due to the large overhead required and strong reliance on CDNs. Certain CDN providers have recently changed their network schemes and policies in response to this threat, however, domain fronting is still possible through some of the minor CDN hosts.

Domain fronting is the exploitation of an encrypted connection to a CDN to gather web resources otherwise blocked by network security measures.

  • First, the client initiates a connection to a legitimate domain (front domain) via HTTP.
  • Second, the originating connection request is read in the clear and is inspected by network security measures.
  • Third, an HTTPS connection is created when the connection is encrypted with an SSL layer, allowing the contents of the traffic to bypass inspection.
  • Finally, The HTTP Host header is read by the server for the resources needed.

The HTTP host header, for this technique, is manipulated to gather resources from a nefarious site on the same CDN. The connection to the manipulated HTTP host header inside the encrypted traffic bypasses network security measures that don’t decrypt the traffic.

For domain fronting to work, the nefarious site and the legitimate site must both be hosted by the same CDN. The ability to pull resources from other sites works because of the inner networking of the CDN and the routing access availability to other parts of their hosting environment. This technique is also utilized with The Onion Router (TOR) node bridges and the meek protocol. The Russian hacker group that breached the Democratic National Committee in 2016, APT29, also known as Cozy Bear, used the TOR meek protocol for their C2 infrastructure communication. Figure 1 gives an overview of this technique.

Figure 1 Technique of domain fronting to bypass inspection.

Google and Amazon CDNs mitigated this technique by preventing any routing from one owner’s site to another. This is done by matching the HTTP host header with the original server name indication (SNI) request, implemented in late April and early May 2018. Since then, Cofense Intelligence has seen an increase in the number of phishing campaigns delivering malware in which the C2 was hosted by Cloudflare.

Figure 2 shows the contrast in Cloudflare C2 seen used by malware before and after May 2018, when Google and Amazon imposed barriers to such activity on their CDNs.

Figure 2 Analyzed C2’s hosted on Cloudflare before and after May 2018.

Figure 3 shows the breakdown of malware families that have used Cloudflare for C2 infrastructure after May of this year.

Figure 3 Malware families utilizing C2’s hosted by Cloudflare since May 2018.

Figure 4 shows the number of different hosts hosted by Cloudflare to which each malware family connects.

Figure 4 Number of C2’s hosted by Cloudflare for each malware family.

Domain fronting has been used by hacktivists and threat actors like APT29 to conceal their malicious activity. CDNs are starting to take the necessary steps to mitigate domain fronting by negating routing from one owner’s site to another, but this ability still persists because it allows for routing to take place among a single owner’s sites.

Defending against this type of communication is a heavy lift for the information technology team. Stopping a malicious email campaign within the email security stack before it gets to the end user’s inbox, and training users to identify phish that do reach their inboxes, are keys to helping mitigate this evasive exfiltration techniques like domain fronting.

Learn more about how Cofense stops active phishing threats.

 

All third-party trademarks referenced by Cofense whether in logo form, name form or product form, or otherwise, remain the property of their respective holders, and use of these trademarks in no way indicates any relationship between Cofense and the holders of the trademarks.

TV-License Phishing Scam Tricks UK Users Into Giving Personal Information

Cofense Intelligence recently observed a new phishing scam making the rounds in the United Kingdom. It poses as the TV licensing authority better known as the British Broadcasting Corporation. The premise behind the scam is to trick the user into believing that he or she is breaking the law by not owning a valid license to receive TV, a criminal offense in the UK with a maximum penalty of a £1000 fine plus any legal costs incurred during prosecution.  

2018: A Reverse-Course for Ransomware

By Mollie MacDougall

The overall number of ransomware campaigns and active families has declined precipitously in 2018 as compared to last year, almost certainly due to multiple deterrents and a better alternative for profit-minded hackers. This reverse-course in ransomware trends follows years of sustained growth in the number of ransomware families and unique campaigns. Still, ransomware attacks make headlines and will likely continue into next year.

Bah HumBUG: 5 Recent Holiday Phishing Samples You Need to Watch Out For

Along with more online shopping, correspondence, and travel, the holiday season sees an increase in phishing operators eager to capitalize on a more-active attack surface. With Thanksgiving tomorrow, Cofense Intelligence and the Cofense Phishing Defense Center have seen a bombardment of Thanksgiving-themed phishing lures this week. Threat actors use this inundation of emails to their advantage—hoping to trick anyone looking for a good deal or eager to partake in the season’s merriment.

Major US Financial Institutions Imitated in Advanced Geodo/Emotet Phishing Lures that Appear More Authentic by Containing ProofPoint URL Wrapped Links

By Darrel Rendell, Mollie MacDougall, and Max Gannon

Cofense IntelligenceTM has observed Geodo (also known as Emotet) malware campaigns that are effectively spoofing major US financial institutions in part by including legitimate URLs wrapped in Proofpoint’s (PFPT) TAP URL Defense wrapping service. This adds an air of legitimacy to the casual observer, designed to increase the chances of malware infection.

Figures 1 and 2 provide examples of the template and URL wrapping. Cofense Intelligence assesses the improved phishing templates are likely based upon data pilfered with a recently updated scraper module to spoof US financial institutions so effectively.

Figure 1: email template spoofing a major US financial institution

Figure 2: Proofpoint’s URL Wrapping service appearing within this campaign

After a month-long hiatus, Geodo returned on November 6th, 2018 with upgrades to its spamming module, supplementing existing capabilities – namely contact list and signature block theft – with functionality enabling the theft of up to 16KB of raw emails and threads. Although the exact reason for this module upgrade was unclear, Cofense Intelligence assessed it would either be used to bolster the actors’ social engineering efforts, using the stolen data to refine Geodo phishing templates, or for direct revenue generation – selling the raw message content to the highest bidder.  Today, it appears the initial prediction was correct.

The campaign observed on November 13th was, in many ways, a standard Geodo campaign: messages distributed en masse to targets across the globe, spoofing a known and trusted organization, containing URLs (Table 1) pointing to Word documents containing hostile macros (Table 2). When executed, these macros retrieve a fresh sample of Geodo from one of five compromised web servers and execute it on the machine. As has become increasingly common with Geodo campaigns, the malware functioned as a downloader for other payloads, in this case retrieving a sample of IcedID.

IcedID shares some basic behavior with TrickBot—another prolific banking trojan turned multipurpose botnet. However, IcedID targets both investment and financial institutions as well as several bank holding companies many of which even TrickBot does not target, as TrickBot is much less focused on investment banks or smaller US commercial banks. An example of an IcedID spoofed login page for a regional US bank can be seen in Figure 3.

Figure 3: a spoofed login page for a regional bank that led to a Geodo and subsequent IcedID payload

Geodo has always been a formidable botnet and continues to grow. During tracking, we have seen at least 20,000 credentials added to the list of credentials used by the botnet clients each week along with millions upon millions of recipients. The introduction of this new module has had clear and dramatic effects on the sophistication and efficacy of this social engineering effort. In July, Geodo began including more sophisticated phishing lures, imitating US banks and including graphics that made the emails look less generic and more convincing.

This most recent campaign demonstrated a shocking improvement from that initial upgrade, demonstrating the value of the email scraping module. Considering that where Geodo goes, TrickBot often follows, we are concerned that this type of module will show up in other malware campaigns. The new inclusion of ProofPoint URLs wrapped with URL Defense adds an additional false sense of security to a user and may indicate the malware scraped the wrapped URLs from a compromised user.

Several members of the Cofense Intelligence team discussed Geodo in a recent open customer call. Any customers who were unable to attend are welcome to email mark.adams@cofense.com for a recording.

Cofense is also offering a complimentary Domain Impact Assessment, powered by the Cofense Research and Intelligence teams, for any organization that may be affected by this Geodo update. Learn more here.

Table 1: Payload URLs observed during this campaign

Table 2: Files associated with this campaign

Table 3: Command and Control infrastructure identified during this campaign

All third-party trademarks referenced by Cofense whether in logo form, name form or product form, or otherwise, remain the property of their respective holders, and use of these trademarks in no way indicates any relationship between Cofense and the holders of the trademarks.

Phishing Emails with .COM Extensions Are Hitting Finance Departments

Cofense IntelligenceTM has seen a substantial uptick in the use of .com extensions in phishing emails that target financial service departments. In October alone, Cofense Intelligence analyzed 132 unique samples with the .com extension, compared to only 34 samples analyzed in all nine months preceding. Four different malware families were utilized.

The .com file extension is used for text files with executable byte code. Both DOS (Disk Operating System) and Microsoft NT kernel-based operating systems allow execution of .com files for backwards compatibility reasons. The .com style byte code is the same across all PE32 binaries (.exe, .dll, .scr, etc.) within the DOS stub. The subject lines and email contents of the phishing emails (Figure 1) suggest that the threat actor is targeting financial service departments. The .iso file attachment mentioned in the email contents is an archive containing a .com1 executable.

Figure 1: Email Content Suggests Targeting of Financial Services Department

If you’re a Cofense PhishMe™ customer, you can use this same lure in your phishing simulations. Look for the template we’ve created, “Overdue Invoice – LokiBot.” It conditions employees to report phishes trying to deliver the Loki Bot information stealer malware. (More on Loki Bot and other malware below).

The two most popular subject line themes we’re seeing use the lures “payment” and “purchase order.” Threat actors are likely carrying out these campaigns to target employees with financial information stored on their local machines, which explains the use of information-stealing malware as the campaigns’ payloads.

Figure 2: Subject Line Categories used in .COM Campaigns

Our analyses showed that the email subject lines were specific to the malware payloads they delivered. For example, the “payment” subject-emails delivered more AZORult information stealer, while the “purchase order” subject-emails most often delivered the Loki Bot information stealer and the Hawkeye keylogger. It is possible that different actors are distributing the unique malware families via .com files. Or, perhaps the same group is responsible and assesses which lures are most appropriate for different malware and the information they target.

Most commonly, .com payloads are directly attached to a phishing email without any intermediary delivery mechanism. However, some campaigns did include an attachment that contained such an intermediary dropper: often the attachment was weaponized to exploit a CVE or a malicious macro, which would deploy a .com payload onto the endpoint. As network defenders become increasingly aware of this direct-attachment delivery, Cofense Intelligence expects to see an increase in intermediary delivery of malicious .com files, wherein a “dropper” attachment will arrive with the phish and subsequently load the weaponized .com file onto the end point.

Figure 3: Malware Families Delivered using .com Extensions.

Loki Bot, AZORult and Hawkeye made up the far majority of malware delivered in the campaigns we analyzed, whereas Pony accounted for a very small percentage. The combination section refers to the attachment utilizing a vulnerability within a document to deploy a .com payload on the endpoint as mentioned above.

The malware families delivered with the .com extension also revealed a trend with their Command and Control (C2) communication. The samples of .com binaries that delivered AZORult communicated exclusively with domains hosted by Cloudflare. Cloudflare was also the predominant host for Loki Bot with over 75% of its C2 domains hosted with that service. It is likely that Cloudflare is not hosting the actual C2, but in fact being used as a domain front. “Domain fronting” is a technique that allows for the connection to appear to go to one domain when it is actually going to another. This is achieved by connecting securely to one domain and then passing in the target domain via the HTTP host header value. By using Cloudflare, which is typically trusted by most organizations, the attackers are able to circumvent blocks that might be put in place. Cloudflare recently changed its policies to disallow its use for malicious hosting, yet the service has continued to be used by attackers for malicious redirection.

Figure 4 below shows the C2’s for Loki Bot, AZORult, and Pony that were hosted on Cloudflare compared to every other domain hosting service provider. Hawkeye keylogger stood apart in communicating with unique email domains.

Cofense Intelligence estimates that we’ll see an increased adoption of malware using the .com extension. Similar campaigns will likely expand to other industries that have monetizable data, like the healthcare and telecommunication sectors. An increased use of the .com extensions can be harmful to enterprise networks if organizations are not prepared for it, and once they are, another file extension will surge in popularity in a constant effort to stay ahead of the defense.

To stay ahead of the latest phishing and malware threats, sign up for free Cofense Threat Alerts.

  1. Filename: overdue payment.com MD5 hash: 8e6f9c6a1bde78b5053ccab208fae8fd

 

All third-party trademarks referenced by Cofense whether in logo form, name form or product form, or otherwise, remain the property of their respective holders, and use of these trademarks in no way indicates any relationship between Cofense and the holders of the trademarks.

Re: The Zombie Phish

By: Lucas Ashbaugh, Nick Guarino, Max Gannon

Out of nowhere, someone responds to an email conversation that wrapped up months ago. It’s a real conversation that actually happened. Maybe it’s about a meeting, a job opportunity, or a reply to that problem you had over a year ago; this email is highly relevant to you. But something is off, the topic of the email is months out of date and now there is a weird error message.

This is a devious tactic, reviving an email conversation long dead – it’s the Zombie Phish.

Not Your Average Phish
The Cofense™ Phishing Defense Center (PDC) has recently been defending against an extensive Zombie Phishing campaign against multiple clients. Fraudsters hijack a compromised email account, and using that account’s inbox, reply to long dead conversations with a phishing link or malicious attachment. Due to the subject of the email being directly relevant to the victim, a curious click is highly likely to occur.

These Zombie Phish appear to use automatically generated infection URLs to evade detection. No two links are the same. These links are hidden behind unassuming “error” messages in the body of the email, providing an appealing scheme for users to fall victim to. Thus far, the PDC has observed two common Zombie Phishing templates that lead to malicious links. These email campaigns can be seen in Figures 1 and 2.

Figure 1

Figure 2

Another common hallmark of this campaign is the use of the .icu top-level domain (TLD), however this could change in the future. Example domains identified during this campaign, which abuse the .icu TLD, can be seen in Figure 3.

Figure 3 shows .icu domains associated with these campaigns.

Already, many of these domains have been shut down by their domain registrar after receiving reports of domain abuse. Figure 4 shows a domain associated with this campaign and the data that is collected and displayed by the registrar.

Figure 4, Courtesy of http://whois.domaintools.com

Additionally, the PDC has observed these phish using official organizational logos to add legitimacy to fake login pages – an example of such can be seen in figure 5. The pages are designed to impersonate an online portal of the target, including the company’s logo, and even its favicon. The end goal is credential theft of the victim.

Figure 5

Finally, any victim that visits the malicious website is “fingerprinted” using the host’s IP address as an identifier and upon entering credentials is immediately redirected to the same spam website seen by other victims. This is often via links obfuscated using URL shorteners (such as hxxps://href[.]li/). If the same host attempts to visit the phishing link again the spoofed login page is skipped and instead you are forwarded directly to the spam page. This finger-printing and the URL shortener obfuscation helps the attackers keep a low profile and continue their campaign unabated.

Conversation Hijacking
The tactic of “conversation hijacking” itself is by no means new, fraudsters have been hijacking compromised email accounts to dish out malware and phish as replies to prior conversations for years now. This technique is still popular because it makes victims much more likely to click on links and download or open files because their guard is down when these are within conversations already in their inbox. An ongoing and currently in the wild example of this is the Geodo botnet which has a history of inserting itself into existing email threads to deliver malicious documents that in turn download a sample of Geodo or other malware like Ursnif. However, the effectiveness of this tactic can depend greatly on the content of the conversations, a response to an automated advertising email is less likely to result in an infection than a response to a help desk support thread such as the one seen in Figure 6. Cofense IntelligenceTM has seen several Geodo campaigns consisting of responses to automated advertising emails indicating that, in some cases, the campaigns consist of indiscriminate responses to all emails in an inbox. Given that the volume of these “conversation hijacking” campaigns is still comparatively low, the smaller scope of these emails is likely limited by the number of ongoing conversations. Certain types of accounts therefore are more likely to draw threat actors direct attention and to induce them to invest additional effort and time into developing unique phishing campaigns for those accounts.

Preventing Your Personal Zombie Apocalypse
The PDC has compiled these quick tips to avoid losing your credentials (or your brains) to a Zombie Phish:

  • Be alert for email subjects that may appear relevant but are from old conversations.
  • Watch out for the hallmark green “error” button (pictured above in figure 1).
  • Don’t trust attached documents simply because they are replying to a conversation.
  • Mouse over buttons or links in suspicious messages to check them for the “.icu” top-level domain.

Cofense’s Phishing Defense CenterTM has observed that these campaigns have become increasingly clever, to combat this, training employees to be able to spot these types of emails is key. You can put down your nail-bats and pitchforks – a properly trained workforce is what is needed to defend your organization against the Zombie Phish hordes.

Cofense offers comprehensive phishing training to arm your employees with the weapons they need to protect your organization. And if you need reinforcements to help against the hordes, the Cofense Phishing Defense Center is happy to do battle with you.

All third-party trademarks referenced by Cofense whether in logo form, name form or product form, or otherwise, remain the property of their respective holders, and use of these trademarks in no way indicates any relationship between Cofense and the holders of the trademarks.

Indicators of Compromise:

Observed Domains
message-akbq[.]cdnmsgload[.]icu

id-Wdtd[.]cdnmsgload[.]icu

message-XPsO[.]cdnmsgload[.]icu

www-jaus[.]check256ssl[.]icu

www-gcgc[.]emailmobile[.]icu

www-wNZq[.]emailmobile[.]icu

message-ncvm[.]emailmobile[.]icu

message-fbfa[.]extmailread[.]icu

www-gwXs[.]fetchemailgo[.]icu

message-jkgj[.]fetchemailgo[.]icu

www-udzi[.]fetchemailgo[.]icu

www-DQcE[.]inboxloaderror[.]icu

message-rpaK[.]inboxloaderror[.]icu

id-jPXC[.]iosemail[.]icu

id-oexq[.]iosemail[.]icu

www-BEOb[.]iosemail[.]icu

id-hKHR[.]iosemail[.]icu

message-EQdH[.]loadcdnmsg[.]icu

www-IqMJ[.]loadcdnmsg[.]icu

message-kqif[.]loading8[.]icu

message-pzvv[.]loading8[.]icu

www-qtnt[.]loading8[.]icu

id-pjgx[.]loading8[.]icu

www-ZMZs[.]loading8[.]icu

www-YIjn[.]loading8[.]icu

message-spuj[.]mail-load[.]icu

www-stxs[.]msgmailweb[.]icu

message-cmmh[.]portalmail[.]icu

message-pcsf[.]secure2[.]icu

id-amjs[.]securemail1[.]icu

www-tesj[.]userclientmsg[.]icu

 

Observed IPs

198[.]46[.]131[.]54

192[.]3[.]202[.]53

“Brazilian Election” Themed Phish Target Users with South American-Targeted Malware, Astaroth Trojan

Threat actors attempted to leverage the current Brazilian presidential election to distribute the Astaroth WMIC Trojan to Brazilian victims. The emails had a subject line related to an alleged scandal involving Brazilian then-presidential candidate Jair Bolsonaro. Some campaigns impersonated a well-known Brazilian research and statistics company. Multiple delivery methods and geolocation techniques were used to target Brazilian users, who were encouraged to interact with the attached and downloaded archives containing .lnk files. These files downloaded the first stage of the Astaroth WMIC Trojan, previously spotted this year by the Cofense Phishing Defense Center and known to target South American users.