Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Vulnerabilities / Threats //

Advanced Threats

2/18/2016
04:50 PM
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
100%
0%

Here Comes Locky, A Brand New Ransomware Threat

Infected Word files being used to spread ransomware, security researchers say.

If it sometimes feels like it's raining ransomware threats these days, that’s only because it is.

Cyber crooks, obviously buoyed by the growing success of their peers with using such malware, have been releasing more versions with alarming regularity. The newest one to join the increasingly crowded ranks of ransomware tools is "Locky," a somewhat awkwardly named but just as dangerous tool as the ones already floating out there.

UK-based security researcher Kevin Beaumont, who was one of the first to report on the new strain, on Wednesday reported seeing around 4,000 new infections per hour, or roughly 100,000 per day. When initially spotted about four days ago, Locky was detectable by just three antivirus products from what Beaumont described as niche vendors. Since then security vendors have updated their signatures and most major AV products now detect the malware Beaumont said in a post last updated Wednesday.

As with other ransomware tools,the operators of Locky are using it to encrypt content on infected systems and then to extract a ransom from victims in return for decrypting the content--in this case about half a Bitcoin, or roughly $210 at today’s rates.

Security researcher Lawrence Abrams, who has also been tracking Locky, described it as targeting a large number of file extensions on infected systems. “Even more importantly [it] encrypts data on unmapped network shares,” he said in a blog post on BleepingComputer.com.

“Encrypting data on unmapped network shares is trivial to code,” he said. The fact that another recent ransomware tool, dubbed DMA Locker, had the exact capability suggests this will become the norm going forward, he said. Locky is also similar to CryptoWall in that it changes the filenames for files it encrypts, making it harder to restore the right data, he added.

Locky is being distributed via a Microsoft Word attachment with malicious macros in it. Victims typically receive an email with an attached Word document purporting to be an invoice seeking payment for some product or service. Recipients who click on the attachment are presented with a document containing scrambled content and an instruction to click on an Office macro to unscramble it. Once enabled, the macro downloads Locky, stores it in the Temp folder and executes it.

Stu Sjouwerman, CEO of security vendor KnowBe4 said one way for enterprises to mitigate the risk is to disable all except digitally signed Office macros from running. If implemented correctly, users will not even see the prompt asking them to enable a macro when they click on the Word document attachment that is being used to distribute Locky, he said in a blog post outlining the steps security admins can take to disable macros.

Threat actors have been using ransomware tools like Locky to devastating effect recently. Just this week for instance, Hollywood Presbyterian Medical Center in Los Angeles said it was the victim of a ransomware attack that ended with it having to pay a ransom of $17,000 to get attackers to unlock the hospital data they had encrypted.

The success of these attacks suggest that the ransomware problem is not going anywhere soon says, Dodi Glenn, vice president of cybersecurity at PC Pitstop in comments to Dark Reading. “The actors behind [such attacks] are financially stable enough to continue to build newer versions of the malware. It is crucial to have important data backed up and stored offline in the event you are hit with ransomware,” he says.

Traditional blacklist antivirus engines have been having a hard time catching ransomware because malware authors are constantly changing portions of the code to remain undetected, he said. “Services like VirusTotal.com allow the hacker to upload newly created malware to see what any of the 54 different antivirus vendors say about the file. They will continue to tweak the file until no vendor detects it,” he said.

Jai Vijayan is a seasoned technology reporter with over 20 years of experience in IT trade journalism. He was most recently a Senior Editor at Computerworld, where he covered information security and data privacy issues for the publication. Over the course of his 20-year ... View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
RyanSepe
50%
50%
RyanSepe,
User Rank: Ninja
2/19/2016 | 8:56:08 AM
17,000 paid
Very surprising that the hospital decided to pay the ransom. I suppose they did not have sufficient backups in place. Moving forward they will hopefully be better equipped after this snafu.
RyanSepe
50%
50%
RyanSepe,
User Rank: Ninja
2/19/2016 | 8:53:50 AM
1990's
Interesting that Locky is using macros to encrypt data. Feels nostalgic of the 1990 macros that were prevalent. In this case easily mitigated with the disabling the execution of macros within office.
COVID-19: Latest Security News & Commentary
Dark Reading Staff 9/25/2020
Hacking Yourself: Marie Moe and Pacemaker Security
Gary McGraw Ph.D., Co-founder Berryville Institute of Machine Learning,  9/21/2020
Startup Aims to Map and Track All the IT and Security Things
Kelly Jackson Higgins, Executive Editor at Dark Reading,  9/22/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
The State of Ransomware
The State of Ransomware
Ransomware has become one of the most prevalent new cybersecurity threats faced by today's enterprises. This new report from Dark Reading includes feedback from IT and IT security professionals about their organization's ransomware experiences, defense plans, and malware challenges. Find out what they had to say!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-15208
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, when determining the common dimension size of two tensors, TFLite uses a `DCHECK` which is no-op outside of debug compilation modes. Since the function always returns the dimension of the first tensor, malicious attackers can ...
CVE-2020-15209
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, a crafted TFLite model can force a node to have as input a tensor backed by a `nullptr` buffer. This can be achieved by changing a buffer index in the flatbuffer serialization to convert a read-only tensor to a read-write one....
CVE-2020-15210
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, if a TFLite saved model uses the same tensor as both input and output of an operator, then, depending on the operator, we can observe a segmentation fault or just memory corruption. We have patched the issue in d58c96946b and ...
CVE-2020-15211
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, saved models in the flatbuffer format use a double indexing scheme: a model has a set of subgraphs, each subgraph has a set of operators and each operator has a set of input/output tensors. The flatbuffer format uses indices f...
CVE-2020-15212
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 2.2.1 and 2.3.1, models using segment sum can trigger writes outside of bounds of heap allocated buffers by inserting negative elements in the segment ids tensor. Users having access to `segment_ids_data` can alter `output_index` and then write to outside of `outpu...