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.

Threat Intelligence

2/27/2019
12:00 PM
Connect Directly
Twitter
LinkedIn
Google+
RSS
E-Mail
50%
50%

Whose Line Is It? When Voice Phishing Attacks Get Sneaky

Researchers investigate malicious apps designed to intercept calls to legitimate numbers, making voice phishing attacks harder to detect.

What if social engineers, instead of calling victims with voice phishing attacks, intercepted phone calls their victims make to legitimate phone numbers? Malicious apps let cybercriminals do just that – a tactic that puts a subtle twist on traditional voice phishing.

Min-Chang Jang, manager at Korea Financial Security Institute and Korea University, began investigating these apps in September 2017 when he received a report of an app impersonating a financial firm. Analysis revealed a phone interception feature in the app, which intrigued him.

That's how Jang discovered a new type of voice phishing crime, which combines traditional voice phishing with malicious apps to trick unsuspecting callers into chatting with cybercriminals.

Here's how they work: An attacker must first convince a victim to download an app. The attacker may send a link to the victim, enticing the person with something like a low-interest loan, and prompt him to install the app for it. If the target takes the bait and later calls a financial company for loan consultation, the call is intercepted and connected to the attacker.

"The victims believe that they are talking to a financial company employee, but they aren't," Jang says. It's unlikely victims will know a scam is taking place, he says. Most of these attacks mimic apps from financial firms.

Unfortunately, when Jang and his research team first discovered malicious apps with the interception feature, they didn't have access to a live malicious app distribution server because it had already been closed by the time they received victim reports. In April 2018, Jang found a live distribution server – a pivotal point for their research into malicious phishing apps.

This particular distribution server had a very short operating cycle, ranging from a few hours to two days. "I found it while monitoring community sites for the information gathering," Jang explains. He discovered a post written to educate users to be careful of phishing sites; fortunately, it discussed the malicious applications they were hoping to investigate.

"I found a specific string in the Web page source code of a live malware distribution server," he says, "and I used the string for scanning to get more malware distribution servers." 

With access to one server, researchers could check which of its ports were open and access the Web page source code. Based on those strings of code from the first distribution server, they were able to create a real-time malicious app collection script, Jang explains. The automated system they created is able to collect malware distribution servers and apps in near real time.

Using this script, researchers have been able to find malicious app distribution servers and variant malicious apps. Following their discovery of the first live distribution server, they have collected about 3,000 malicious apps from various servers. The command-and-control (C2) server address was hard-coded inside malicious apps, Jang says, and could be easily extracted.

Their research continued to unfold. The team analyzed the C2 server, where they discovered a file containing the account data they needed to access it. This data helped the team gain the privileges of the Windows server admin of the distribution server and of the database admin of the C2 server. A Remote Desktop Protocol (RDP) connection to the server led to more information – the team confirmed this attacker was connecting to the Internet via the Point-to-Point Protocol over Ethernet (PPPoE), a sign the server's location was in Taiwan.

In a presentation at Black Hat Asia, entitled "When Voice Phishing Met Malicious Android App," Jang will disclose and discuss the findings of criminal traces in voice phishing analysis conducted by his research team over the past few months.

 

 

Join Dark Reading LIVE for two cybersecurity summits at Interop 2019. Learn from the industry's most knowledgeable IT security experts. Check out the Interop agenda here.

Kelly Sheridan is the Staff Editor at Dark Reading, where she focuses on cybersecurity news and analysis. She is a business technology journalist who previously reported for InformationWeek, where she covered Microsoft, and Insurance & Technology, where she covered financial ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Joe Stanganelli
50%
50%
Joe Stanganelli,
User Rank: Ninja
2/28/2019 | 6:22:38 PM
Re: More app trouble
Yeah, I'm at the point where I just never answer the phone unless I either recognize the number or I'm specifically expecting a call. If it's a real person with a good reason for calling, they'll leave a voicemail.
REISEN1955
50%
50%
REISEN1955,
User Rank: Ninja
2/27/2019 | 3:52:03 PM
Re: More app trouble
Agree - NEVER trust the phone - we get scam calls all of the time and a few i enjoy such as telling the famous Microsoft engineer I have a bug on my system.  Takes anger to good use.  (My former manager is better, he tries then to upload ransomware to THEIR system for the revenge of it).   About 5% of inicoming calls are real and the rest junk.  Silence phone calls to - and spoof phone numbers.  Don't answer really unless sometimes I just want a bit of threathunting to see who calls.  
Joe Stanganelli
50%
50%
Joe Stanganelli,
User Rank: Ninja
2/27/2019 | 2:15:22 PM
More app trouble
Apps, extensions, add-ons, widgets -- just stay away from 'em, people, unless they are very well vetted.
I 'Hacked' My Accounts Using My Mobile Number: Here's What I Learned
Nicole Sette, Director in the Cyber Risk practice of Kroll, a division of Duff & Phelps,  11/19/2019
TPM-Fail: What It Means & What to Do About It
Ari Singer, CTO at TrustPhi,  11/19/2019
Americans Fed Up with Lack of Data Privacy
Robert Lemos, Contributing Writer,  11/18/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Current Issue
Navigating the Deluge of Security Data
In this Tech Digest, Dark Reading shares the experiences of some top security practitioners as they navigate volumes of security data. We examine some examples of how enterprises can cull this data to find the clues they need.
Flash Poll
Rethinking Enterprise Data Defense
Rethinking Enterprise Data Defense
Frustrated with recurring intrusions and breaches, cybersecurity professionals are questioning some of the industrys conventional wisdom. Heres a look at what theyre thinking about.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-19227
PUBLISHED: 2019-11-22
In the AppleTalk subsystem in the Linux kernel before 5.1, there is a potential NULL pointer dereference because register_snap_client may return NULL. This will lead to denial of service in net/appletalk/aarp.c and net/appletalk/ddp.c, as demonstrated by unregister_snap_client, aka CID-9804501fa122.
CVE-2019-10203
PUBLISHED: 2019-11-22
PowerDNS Authoritative daemon , all versions pdns 4.1.x before pdns 4.1.10, exiting when encountering a serial between 2^31 and 2^32-1 while trying to notify a slave leads to DoS.
CVE-2019-10206
PUBLISHED: 2019-11-22
ansible-playbook -k and ansible cli tools, all versions 2.8.x before 2.8.4, all 2.7.x before 2.7.13 and all 2.6.x before 2.6.19, prompt passwords by expanding them from templates as they could contain special characters. Passwords should be wrapped to prevent templates trigger and exposing them.
CVE-2018-10854
PUBLISHED: 2019-11-22
cloudforms version, cloudforms 5.8 and cloudforms 5.9, is vulnerable to a cross-site-scripting. A flaw was found in CloudForms's v2v infrastructure mapping delete feature. A stored cross-site scripting due to improper sanitization of user input in Name field.
CVE-2019-13157
PUBLISHED: 2019-11-22
nsGreen.dll in Naver Vaccine 2.1.4 allows remote attackers to overwrite arbitary files via directory traversal sequences in a filename within nsz archive.