These are quick first looks and trend and threats


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Written by the security and AV professionals from team K7, meant for the general audience
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These are usually articles that go into internals of a virus or deal with security issues
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Senior managers speak on areas of interest to them, inside and outside the industry
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October 21st, 2016

The sensational, massive theft of critical data from Indian debit card holders, and the subsequent abuse of card data in China and USA, have been widely reported in the Indian media.

1421732801789.jpg

Unfortunately the information available seems to be largely based on hearsay and conjecture, some of it even contradictory. The following Donald Rumsfeld (ex-United States Secretary of Defense) quote from February, 2012 comes to mind:

“Reports that say that something <redacted for effect> happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don’t know we don’t know.”

We may use the above quote to analyse the facts or lack thereof:

  • Known knowns – The critical details of lots of cards (32 lakh may be a paranoid extrapolation of the real figures) have been potentially compromised, many of which have been abused in China and USA
  • Known unknowns –  How exactly was the data stolen? Was there really ATM malware or some skimming device? Or was there a breach on the backend ATM infrastructure either via malware or via direct database hacking? How was the stolen data relayed back to the cyber criminals?
  • Unknown unknowns – Given the nature of this breach, what other parts of the ATM and banking networked infrastructure are vulnerable to attack? What will those scary headlines read in the future?

We are still in the hunt for real technical detail relevant to this particular breach. Malware samples or hashes would be very useful.

ATM and Point of Sale (PoS) malware are not a recent phenomenon. ATMs can be considered to be computers with some customised hardware, e.g. card reader, attached. They tend to:

  • run Windows XP as the OS hosting the ATM services
  • have no Anti-Virus software installed
  • perhaps employ inadequate encryption mechanisms to prevent the leakage of transaction data

Obviously these factors are not conducive to the maintenance of data security on ATM networks. Windows XP is known to be vulnerable and has been unsupported by Microsoft since 2014! Regardless of the true nature of the current breach it seems clear that the banking industry does need to take ATM security more seriously than employing security guards outside terminals who may doze, if even present, or worse. A good place to start would be to address the vulnerabilities highlighted above, i.e.:

  1. Upgrade the host OS to a more secure, light-weight one, and ensure that it is adequately patched
  2. Install customised Anti-Virus software with slim, relevant security updates
  3. Employ industry-standard encryption (AES/RSA/ECDH, etc.) across critical data transfer channels and storage areas
  4. Get the whole infrastructure vetted by competent third-party agencies through black-box (vulnerability assessment, pen testing, etc.), and white-box (code review) mechanisms

We shall keenly monitor developments in this case, especially if samples are forthcoming.

Image by Karl Hilzinger courtesy of:

http://www.smh.com.au/it-pro/security-it/credit-card-fraud-8-ways-your-details-can-be-hijacked-20150119-12ttwn.html

Samir Mody
AVP, K7TCL

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September 30th, 2016

Continuing our series on Cyber Security, this blog post aims to shed some light on a security term that is casually thrown around these days, Denial-of-Service.

As the term conveys a “Denial-of- Service” (DoS) attack aims to cut off the provision of a service. When we speak of it in terms of computing we would generally refer to an online network-based service that is renderred inaccessible to legitimate users during the course of the attack. A successful DoS attack would require a large number of requests being sent to the network service at a specific point in time.

In general for a seamless network communication to happen a “request-acknowledge” signal is essential, i.e. when a user makes a request to a network service his request would first be acknowledged and then data corresponding to his query would be sent back along with a request for acknowledgement once the data is received. The user then sends an acknowledge signal once the requested data has been received. All this happens in the order of milliseconds hence they are barely noticeable.

Every server that hosts a service would have a maximum request-handling capacity, and when that threshold is exceeded the server or the service becomes unavailable. It is this request limit which is exploited and abused by a DoS attack.

When speaking in terms of malware related DoS, malware authors employ their botnet (a collection of computers infected with silently-running backdoor Trojans) to perform this kind of attack. A botnet controller (aka “Bot Master”) can send out instructions to the entire botnet under his command to target a specific service, typically a web service, to effect a DoS on the target website.

Several DoS attacks have been orchestrated targeting organizations along with ransom demands to call off the attack. In the days of e-commerce and online services it is essentials that business organizations keep their services up and running in order to retain their customer base.

In this series we shall have a look at various flavours of DoS attacks and how they are orchestrated.

Image Courtesy of:
tgm.org

K7 Threat Control Lab

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September 12th, 2016

Last week one of our Enterprise customers reported that they had received an email threatening them with a DDos attack on their allegedly vulnerable servers if one bitcoin (about US$600) were not paid to them. Furthermore, to force a greater sense of panic, there was a threat of spreading nasty ransomware on their network.

The extortionary email resembled the following:

It turns out that this so called “Armada Collective” group has made similar ransom demands in the past, and the threat has always turned out to be fake to date. No occurrence of an actual DDos attack has yet been reported by the Enterprise customer who received the aforementioned threat or by any of our other customers.

Of course there are real world examples of DDoS attacks which target businesses but the attackers’ modus operandi is typically different from that described above. Historically many DDoS attacks have taken place without prior warning and without a ransom demand.

If any of our customers or any other businesses receive threatening messages of the form shown above we recommend that you do not panic as there is no proof of an actual attack by these scaremongering cyber criminals disguised as “Armada Collective”. There is certainly no need to pay the ransom demanded. Instead we recommend that you implement adequate boundary-level protection for your servers and network, and assess/pen-test the servers for potential vulnerabilities to be identified and mitigated against ASAP.

Image courtesy of newspeechtopics.com

Samir Mody
K7 Threat Control Lab

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September 2nd, 2016

K7 Computing celebrated its 24th anniversary last week with the annual “bay decoration” event, which puts to the test teamwork, camaraderie, creativity and sheer effort, of course. The following collage should give you an idea of how our workspaces were transformed for a day.

Enjoy…

K7 Team

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August 19th, 2016

This week’s hot news within network security circles is likely to be about the most recent update to the TCP specification which allegedly allows communication channels to be hijacked by a remote attacker. This latest TCP specification has been implemented on Linux systems, but is yet to be on Windows, apparently.

This is essentially an information disclosure flaw. The latest TCP specification may leak information about established, active connections through a side channel. The researchers who discovered the flaw claim it could allow a hacker to insert malicious or unwanted data packets into a data packet series between any two arbitrary machines whose IPs are known. Interestingly this Man-in-the-Middle type scenario would not require the attacker to insert himself/herself on the same communication channel as the connected target machines.

How serious is this flaw to a typical end user, though? To attack an end user, a hacker would need to identify a spoofed IP address to pretend to come from a specific source with which the user has already established a connection, and the user’s own target IP address. Hence, the probability that any specific user gets targeted at random is less, the reason being that there is a huge user base of dynamically-allocated IPs. Exploitation of the flaw could be more likely to succeed in IPv4 cases, but with the introduction of IPv6 the probability that an individual user’s IP would be found at random is small, both in the case of mobile devices and desktop computers.

Given the nature of an attempted attack perhaps this flaw will be more worrisome to web servers, etc., which are required to be ON all the time, and more likely to have predictable IPs.

As for the malware injection claim, it seems less likely that a malware payload by itself would be sent within a data packet. Rather, it could be a malicious URL that redirects the user to download the malware.

Installing a reputed and updated security product like K7 Total Security should block any malicious URLs being accessed or malicious files from being downloaded onto a victim’s computer.

Image courtesy: wakinguptheghost.com

Samir Mody, K7 Threat Control Lab
V.Dhanalakshmi, K7 Threat Control Lab

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August 11th, 2016

Shattering the period of calm after the discovery of Android Stagefright exploit, Android Quadrooter has become the current hot topic in the mobile security industry. Quadrooter, as its name suggests, is a group of four vulnerabilities in the software drivers for Qualcomm chipsets within certain Android devices.  These drivers are responsible for communication between chipset components in the Android packages developed by the manufacturer.

Exploiting any one of these four vulnerabilities in the drivers would provide a hacker with root access on the device. Unlike Stagefright, which was exploitable via remotely sent crafted messages, these Quadrooter vulnerabilities are apparently exploitable only through apps which must be explicitly downloaded and installed by the user.  Although this is may be considered another dangerous method that hackers can incorporate into their malware to attain root permissions, at the time of writing, not a single actual sample has been found in the wild.

Patching the vulnerable software drivers with appropriate security updates would be the most suitable solution to mitigate the risk caused by these vulnerabilities. However it is a never ending debate whether a security update from Google (or Qualcomm, etc.,) can be customized to suit a handset manufacturer’s model within a reasonable time frame. In fact how quickly does a manufacturer’s customized security update reach its own users’ devices? “ .

The  good news is that Google claims that these exploits can be blocked by the “Verify Apps” feature in the Android OS from version 4.2 (Jelly Bean). Locate this feature at:

Settings>System>Security>Verify Apps

Here are a few steps to follow to help avoid dangerous security issues when downloading an application and other unwanted scenarios:

  • Always prefer to download an application from the official Google Play
  • Think twice before you download an application whether you really need it
  • Check any documented usage of the application to ensure that it does not perform any functionality separate from your expectations
  • Verify the reputation of the application by checking the reviews available
  • Avoid using free Wi-Fi hotspots, in particular those that are not password protected
  • Install a reputed and up-to-date mobile security product like “K7 Mobile Security”
  • Avail of the available application verification features like “verify apps” in recent Android OSs to identify a malware before installation.

V.Dhanalakshmi
Senior Threat Researcher, K7TCL

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July 13th, 2016

Ransomware, a nasty and, unfortunately, common subclass of malware, are really bad news. The good news, however, is that K7′s heuristic, dynamic behaviour-based anti-ransomware feature, Ransomware Protection, was “productionised” and released some time ago. We strongly believe Ransomware Protection will provide users with robust safeguards against various strains of crypto ransomware, from the past (e.g. CryptoLocker), the present (e.g. Locky) and the future (???).

Ransomware Protection_cropped.png

Ransomware Protection’s blocking logic is based on recognising and arresting fundamental changes that take place in targeted files when the ransomware’s industry-grade encryption algorithms are applied to them.

At the Virus Bulletin 2015 international security conference we demonstrated a PoC of the anti-ransomware technology in our presentation “Dead and Buried in Their Crypts: Defeating Modern Ransomware”, and explained how the technology works in some detail so that all of us in the security industry could implement an effective strategy against this highly-damaging type of malware.

Elevating a PoC to a full-blown production-level feature is a time-consuming process since many factors related to stability, false positives and performance need to be considered in an end user environment. We are delighted to have been able to develop and release an anti-ransomware jab which will boost end-user resistance to any ransomware attack. Your precious documents, images and videos should now be safe. Note, we still highly recommend that you backup your important files as the spectre of bad sectors developing on your hard drive continues to loom large.

Samir Mody, Senior Manager, K7 Threat Control Lab
Gregory Panakkal, Senior Software Architect, K7 Product Engineering Team

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July 8th, 2016

It is possible for even an unintended person to view the personal information you post online, whether from a PC or from a mobile device. Sadly there is a high possibility of ladies being targeted, bullied or harassed. A recent shameful incident reported in the news where a man in Delhi has been arrested for harassing ladies in the region with unsavoury messages or phone calls after viewing their WhatsApp profile pictures.

Enhancements in social networking sites and their applications have attracted a huge user base especially amongst youngsters. As we recommended in our previous blog, online users, ladies  in particular, should be vigilant while posting their personal information like photos, contact details, address, etc., in all social networking forums, even applications that simply connect people around.

Women should also be aware that the information shared online stays forever and is free for public viewing. Reiterating, here are few tips to avoid falling prey to such incidents.

  • Tweak privacy settings in applications carefully to prevent strangers from contacting you
    • WhatsApp > Menu Button > Settings > Account > Privacy
  • Avoid posting your personal pictures online such that anybody can view them
  • Never accept strangers to your contact list
  • Avoid sharing your personal information especially photos, phone numbers, address,etc. online

Image courtesy:
stonehousedesigns.com

V.Dhanalakshmi
Senior Threat Researcher, K7TCL

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June 29th, 2016

A few weeks ago we had announced our intention to spread our knowledge about low-level security. We would like to share a proud moment with the public to demonstrate our commitment to the cause of spreading technical awareness, borne from our decades of experience and expertise in malware research and anti-malware technology development.

We were recently invited by the well-known academic institution, VIT Vellore, to conduct a day-long workshop on the malware analysis techniques we carry out at K7 Threat Control Lab (K7TCL). The idea of the presentation was to enlighten VIT staff on analysis techniques for both Windows and Android malware.

We are happy to have had this opportunity to share our knowledge, and we hope that the interactive session we conducted has helped VIT staff to understand the modern malware threat landscape, and the malware themselves in a more effective way.

Kaarthik.R.M
Shiv Chand.K
V.Dhanalakshmi
K7TCL

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June 16th, 2016

Here is an interesting persistence technique, which I have not seen before, used by a malware which I analyzed last week at K7 Threat Control Lab. It uses a simple RunOnce registry entry to maintain its persistence but in a unique way. I would like to post a complete analysis, albeit brief, of its functionality.

Functionality in a Nutshell

  • Push-Pop-Call
  • Misuse of Process Environment Block (PEB)
  • API Hashing Technique
  • Anti-Debug & Anti-Emulation Techniques
  • Strings Obfuscation Mechanism
  • Registry Abuse
  • Hidden DLL with multiple entrypoints (Export & DLL main) and its role
  • Multiple Injections into explorer.exe
  • Rootkit-like Behavior
  • Persistence Mechanism – RunOnce entry
  • Final Injection to IExplore.exe to act as downloader

Push-Pop-Call

This malware uses a Push-Pop-Call sequence at the Entrypoint to change the execution flow of the program as shown in Figure 1. This is not a clever technique since it can be used by Anti-Virus software to flag the malware immediately given that this sequence is unlikely to be found in clean programs.

Figure 1

Misuse of Process Environment Block (PEB)

Not an uncommon technique, this malware uses PEB_LDR_DATA, a member of the PEB structure, to locate InMemoryOrderModuleList LinkedList, which is then used to retrieve names of the loaded modules. It calculates the hash for each of the retrieved module names and compares with that of Kernel32.dll (hardcoded in the code), and extracts the base address of Kernel32.dll when the hashes match as shown in Figure 2.

Figure 2

API Hashing Technique

Using the retrieved Kernel32.dll base address, it enumerates export function names and calculates their hashes, which, in turn, are compared with predefined API hashes (in the data section) to identify the addresses of preferred APIs that are listed below. This common technique is to avoid heuristic detection on import APIs.

  • ConvertThreadToFiber
  • CreateDirectoryA
  • CreateFiber
  • CreateFileA
  • CreateMutexA
  • CreateProcessA
  • CreateThread
  • DeleteFileA
  • GetFileSize
  • GetFileTime
  • GetModuleFilenameA
  • LoadLibraryA
  • MoveFileExA
  • ReadFile
  • ReleaseMutex
  • RemoveDirectoryA
  • SetFileAttributesA
  • SetFilePointer
  • SetFileTime
  • SwitchtoFiber
  • WaitForMultipleObjects
  • WriteFile
  • WritePrivateProfileStringA

The hash calculation algorithm is shown in Figure 3 below.

Figure 3

Anti-Debug & Anti-Emulation Techniques

It implements Anti-Debug & Anti-Emulation techniques to prevent or misguide the reverse engineering process. This malware creates a thread which possesses an Anti-Debug technique of Memory Access Violation Exception (shown in Figure 4 below), thus complicating the analysis flow for researchers.

Figure 4

It also adds additional Exception Handlers in the existing SEH chain, which would be triggered by a memory access violation as shown in Figure 5.

Figure 5

It also uses undocumented ntdll.dll APIs which could act as an anti-emulation technique

  • ZwCreateThread
  • ZwResumeThread

Strings Obfuscation Mechanism

It employs an uncomplicated obfuscation mechanism to hide strings to dodge its presence from Anti-Virus products. Figure 6 shows how it decrypts a string to be used as its mutex.

Figure 6

Registry Abuse

It uses the registry to find the default path of “user\%AppData%” by querying the following registry key:

Subkey : “Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders”
Value    : “AppData”

It uses the registry to find the default browser path:

Subkey : “http\shell\open\command”

It also escalates its privilege under Internet Explorer by adding its path to the following registry key:

SubKey : “Software\Microsoft\Internet Explorer\LowRegistry”
Value    : “ms-ldr”
Data     : “%Malware Path%”

Hidden DLL with Multiple Entrypoints (Export & DLL Main) and its Role

It drops its main payload, ntuser.cpl (a DLL file), extracted and decrypted from its ‘data’ section, under a randomly named folder in the retrieved %APPDATA% directory as exemplified below:

USER/%APPDATA%/ {6JJ0C2I2-2W3D-2P70-7999-9N8KF3N5}/ntuser.cpl

The decryption logic used is shown below in Figure 7:

Figure 7

It tries harder to misguide analysis by executing the DLL with multiple entrypoints. Initially with the help of rundll32 it executes the dropped ntuser.cpl using its export function “_4CDFA75B”. This export function “_4CDFA75B” then injects the entire ntuser.cpl to explorer.exe with “DLLMain” as its new entrypoint. Injection technique 1 uses the following APIs:

  • CreateProcessA
  • GetModuleFileNameA
  • CreateFileMappingA
  • MapViewOfFile
  • UnmapViewOfFile
  • ZwMapViewOfSection
  • CreateRemoteThread

Multiple Injections into Explorer.exe

As ntuser.cpl loads into the memory space of explorer.exe, it uses the ‘ZwQuerySystemInformation’ API to get the snapshot of the current running processes. Now ntuser.cpl injects itself to the running processes that have access to ‘CREATE_THREAD & VM_OPERATION & VM_WRITE & QUERY_INFORMATION’ permissions, including explorer.exe.  But, this time with a new entrypoint being one of its functions. Injection technique 2 uses the following APIs:

  • OpenProcess
  • VirtualFreeEx
  • VirtualAllocEx
  • VirtualQueryEx
  • VirtualProtectEx
  • WriteProcessMemory
  • VirtualQueryEx
  • CreateRemoteThread

The latest injected code in explorer.exe now injects code into IExplore.exe, again with a new entrypoint being one of its functions using a similar injection technique to that described above.

These multiple injections are done just to halt the flow of analysis and to use system processes to download malicious content which will not trigger any alert by Anti-Virus Software, including Firewall.

Rootkit Behavior

It injects all system processes when attempting to act as a rootkit by hooking the following APIs, to maintain its stealth status:

  • NtCreateThread
  • NtEnumerateValueKey
  • NtQueryDirectoryFile
  • NtResumeThread

Persistence Mechanism

The latest injected code in explorer.exe also has the task of maintaining its persistence. This is achieved by creating a thread which checks the availability of mutex (MSCTF.Shared.MUTEX.LDR) and if this fails, it adds the following RunOnce entry:

SubKey : “Software\Microsoft\Windows\CurrentVersion\RunOnce”
Data      : “rundll32 “%APPDATA%\{6JJ0C2I2-2W3D-2P70-7999-9N8KF3N5}\ntuser.cpl”,_4CDFA75B”

Hence during reboot, the mutex gets killed and immediately a RunOnce entry is registered to maintain persistence.

Final Injection into IExplore.exe to Act as Downloader

Using IExplore.exe injected code, it checks for internet connectivity every 5 minutes, and if it has access to the internet, it uses ‘URLDownloadToFileA’ to download malicious content from the following URL

“hxxp: / /business-links-today.org/ldr/admin/feed.php?i=6JJ0C2I2-2W3D-2P70-7999-9N8KF3N5&o=2&v=1.0.8″

Post downloading it executes the downloaded content using CreateProcessA.

On final analysis this turns out to be just a mere Downloader, with a high level of obfuscation, injection techniques, and Anti-Debugging/Anti-Emulation tricks along with rootkit behavior.

Sample analyzed:

MD5: 6F14315A8875B1CF04E9FDB963E12966
SHA256: B129D92F6C62B7C81B5EF69FA38194AB3886BA7F18230581BC2D241C997F7FA6

Shiv Chand.K
Senior Threat Researcher

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