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Before yesterdayKrebs on Security

Tourists Give Themselves Away by Looking Up. So Do Most Network Intruders.

By BrianKrebs

In large metropolitan areas, tourists are often easy to spot because they’re far more inclined than locals to gaze upward at the surrounding skyscrapers. Security experts say this same tourist dynamic is a dead giveaway in virtually all computer intrusions that lead to devastating attacks like data theft and ransomware, and that more organizations should set simple virtual tripwires that sound the alarm when authorized users and devices are spotted exhibiting this behavior.

In a blog post published last month, Cisco Talos said it was seeing a worrisome “increase in the rate of high-sophistication attacks on network infrastructure.” Cisco’s warning comes amid a flurry of successful data ransom and state-sponsored cyber espionage attacks targeting some of the most well-defended networks on the planet.

But despite their increasing complexity, a great many initial intrusions that lead to data theft could be nipped in the bud if more organizations started looking for the telltale signs of newly-arrived cybercriminals behaving like network tourists, Cisco says.

“One of the most important things to talk about here is that in each of the cases we’ve seen, the threat actors are taking the type of ‘first steps’ that someone who wants to understand (and control) your environment would take,” Cisco’s Hazel Burton wrote. “Examples we have observed include threat actors performing a ‘show config,’ ‘show interface,’ ‘show route,’ ‘show arp table’ and a ‘show CDP neighbor.’ All these actions give the attackers a picture of a router’s perspective of the network, and an understanding of what foothold they have.”

Cisco’s alert concerned espionage attacks from China and Russia that abused vulnerabilities in aging, end-of-life network routers. But at a very important level, it doesn’t matter how or why the attackers got that initial foothold on your network.

It might be zero-day vulnerabilities in your network firewall or file-transfer appliance. Your more immediate and primary concern has to be: How quickly can you detect and detach that initial foothold?

The same tourist behavior that Cisco described attackers exhibiting vis-a-vis older routers is also incredibly common early on in ransomware and data ransom attacks — which often unfurl in secret over days or weeks as attackers methodically identify and compromise a victim’s key network assets.

These virtual hostage situations usually begin with the intruders purchasing access to the target’s network from dark web brokers who resell access to stolen credentials and compromised computers. As a result, when those stolen resources first get used by would-be data thieves, almost invariably the attackers will run a series of basic commands asking the local system to confirm exactly who and where they are on the victim’s network.

This fundamental reality about modern cyberattacks — that cybercriminals almost always orient themselves by “looking up” who and where they are upon entering a foreign network for the first time — forms the business model of an innovative security company called Thinkst, which gives away easy-to-use tripwires or “canaries” that can fire off an alert whenever all sorts of suspicious activity is witnessed.

“Many people have pointed out that there are a handful of commands that are overwhelmingly run by attackers on compromised hosts (and seldom ever by regular users/usage),” the Thinkst website explains. “Reliably alerting when a user on your code-sign server runs whoami.exe can mean the difference between catching a compromise in week-1 (before the attackers dig in) and learning about the attack on CNN.”

These canaries — or “canary tokens” — are meant to be embedded inside regular files, acting much like a web beacon or web bug that tracks when someone opens an email.

The Canary Tokens website from Thinkst Canary lists nearly two-dozen free customizable canaries.

“Imagine doing that, but for file reads, database queries, process executions or patterns in log files,” the Canary Tokens documentation explains. “Canarytokens does all this and more, letting you implant traps in your production systems rather than setting up separate honeypots.”

Thinkst operates alongside a burgeoning industry offering so-called “deception” or “honeypot” services — those designed to confuse, disrupt and entangle network intruders. But in an interview with KrebsOnSecurity, Thinkst founder and CEO Haroon Meer said most deception techniques involve some degree of hubris.

“Meaning, you’ll have deception teams in your network playing spy versus spy with people trying to break in, and it becomes this whole counterintelligence thing,” Meer said. “Nobody really has time for that. Instead, we are saying literally the opposite: That you’ve probably got all these [security improvement] projects that are going to take forever. But while you’re doing all that, just drop these 10 canaries, because everything else is going to take a long time to do.”

The idea here is to lay traps in sensitive areas of your network or web applications where few authorized users should ever trod. Importantly, the canary tokens themselves are useless to an attacker. For example, that AWS canary token sure looks like the digital keys to your cloud, but the token itself offers no access. It’s just a lure for the bad guys, and you get an alert when and if it is ever touched.

One nice thing about canary tokens is that Thinkst gives them away for free. Head over to canarytokens.org, and choose from a drop-down menu of available tokens, including:

-a web bug / URL token, designed to alert when a particular URL is visited;
-a DNS token, which alerts when a hostname is requested;
-an AWS token, which alerts when a specific Amazon Web Services key is used;
-a “custom exe” token, to alert when a specific Windows executable file or DLL is run;
-a “sensitive command” token, to alert when a suspicious Windows command is run.
-a Microsoft Excel/Word token, which alerts when a specific Excel or Word file is accessed.

Much like a “wet paint” sign often encourages people to touch a freshly painted surface anyway, attackers often can’t help themselves when they enter a foreign network and stumble upon what appear to be key digital assets, Meer says.

“If an attacker lands on your server and finds a key to your cloud environment, it’s really hard for them not to try it once,” Meer said. “Also, when these sorts of actors do land in a network, they have to orient themselves, and while doing that they are going to trip canaries.”

Meer says canary tokens are as likely to trip up attackers as they are “red teams,” security experts hired or employed by companies seeking to continuously probe their own computer systems and networks for security weaknesses.

“The concept and use of canary tokens has made me very hesitant to use credentials gained during an engagement, versus finding alternative means to an end goal,” wrote Shubham Shah, a penetration tester and co-founder of the security firm Assetnote. “If the aim is to increase the time taken for attackers, canary tokens work well.”

Thinkst makes money by selling Canary Tools, which are honeypots that emulate full blown systems like Windows servers or IBM mainframes. They deploy in minutes and include a personalized, private Canarytoken server.

“If you’ve got a sophisticated defense team, you can start putting these things in really interesting places,” Meer said. “Everyone says their stuff is simple, but we obsess over it. It’s really got to be so simple that people can’t mess it up. And if it works, it’s the best bang for your security buck you’re going to get.”

Further reading:

Dark Reading: Credential Canaries Create Minefield for Attackers
NCC Group: Extending a Thinkst Canary to Become an Interactive Honeypot
Cruise Automation’s experience deploying canary tokens

Google Suspends Chinese E-Commerce App Pinduoduo Over Malware

By BrianKrebs

Google says it has suspended the app for the Chinese e-commerce giant Pinduoduo after malware was found in versions of the software. The move comes just weeks after Chinese security researchers published an analysis suggesting the popular e-commerce app sought to seize total control over affected devices by exploiting multiple security vulnerabilities in a variety of Android-based smartphones.

In November 2022, researchers at Google’s Project Zero warned about active attacks on Samsung mobile phones which chained together three security vulnerabilities that Samsung patched in March 2021, and which would have allowed an app to add or read any files on the device.

Google said it believes the exploit chain for Samsung devices belonged to a “commercial surveillance vendor,” without elaborating further. The highly technical writeup also did not name the malicious app in question.

On Feb. 28, 2023, researchers at the Chinese security firm DarkNavy published a blog post purporting to show evidence that a major Chinese ecommerce company’s app was using this same three-exploit chain to read user data stored by other apps on the affected device, and to make its app nearly impossible to remove.

DarkNavy likewise did not name the app they said was responsible for the attacks. In fact, the researchers took care to redact the name of the app from multiple code screenshots published in their writeup. DarkNavy did not respond to requests for clarification.

“At present, a large number of end users have complained on multiple social platforms,” reads a translated version of the DarkNavy blog post. “The app has problems such as inexplicable installation, privacy leakage, and inability to uninstall.”

Update, March 27, 1:24 p.m. ET: Dan Goodin over at Ars Technica has an important update on this story that indicates the Pinduoduo code was exploiting a zero-day vulnerability in Android — not Samsung. From that piece:

“A preliminary analysis by Lookout found that at least two off-Play versions of Pinduoduo for Android exploited CVE-2023-20963, the tracking number for an Android vulnerability Google patched in updates that became available to end users two weeks ago. This privilege-escalation flaw, which was exploited prior to Google’s disclosure, allowed the app to perform operations with elevated privileges. The app used these privileges to download code from a developer-designated site and run it within a privileged environment.

“The malicious apps represent “a very sophisticated attack for an app-based malware,” Christoph Hebeisen, one of three Lookout researchers who analyzed the file, wrote in an email. “In recent years, exploits have not usually been seen in the context of mass-distributed apps. Given the extremely intrusive nature of such sophisticated app-based malware, this is an important threat mobile users need to protect against.”

On March 3, 2023, a denizen of the now-defunct cybercrime community BreachForums posted a thread which noted that a unique component of the malicious app code highlighted by DarkNavy also was found in the ecommerce application whose name was apparently redacted from the DarkNavy analysis: Pinduoduo.

A Mar. 3, 2023 post on BreachForums, comparing the redacted code from the DarkNavy analysis with the same function in the Pinduoduo app available for download at the time.

On March 4, 2023, e-commerce expert Liu Huafang posted on the Chinese social media network Weibo that Pinduoduo’s app was using security vulnerabilities to gain market share by stealing user data from its competitors. That Weibo post has since been deleted.

On March 7, the newly created Github account Davinci1010 published a technical analysis claiming that until recently Pinduoduo’s source code included a “backdoor,” a hacking term used to describe code that allows an adversary to remotely and secretly connect to a compromised system at will.

That analysis includes links to archived versions of Pinduoduo’s app released before March 5 (version 6.50 and lower), which is when Davinci1010 says a new version of the app removed the malicious code.

Pinduoduo has not yet responded to requests for comment. Pinduoduo parent company PDD Holdings told Reuters Google has not shared details about why it suspended the app.

The company told CNN that it strongly rejects “the speculation and accusation that Pinduoduo app is malicious just from a generic and non-conclusive response from Google,” and said there were “several apps that have been suspended from Google Play at the same time.”

Pinduoduo is among China’s most popular e-commerce platforms, boasting approximately 900 million monthly active users.

Most of the news coverage of Google’s move against Pinduoduo emphasizes that the malware was found in versions of the Pinduoduo app available outside of Google’s app store — Google Play.

“Off-Play versions of this app that have been found to contain malware have been enforced on via Google Play Protect,” a Google spokesperson said in a statement to Reuters, adding that the Play version of the app has been suspended for security concerns.

However, Google Play is not available to consumers in China. As a result, the app will still be available via other mobile app stores catering to the Chinese market — including those operated by Huawei, Oppo, Tencent and VIVO.

Google said its ban did not affect the PDD Holdings app Temu, which is an online shopping platform in the United States. According to The Washington Post, four of the Apple App Store’s 10 most-downloaded free apps are owned by Chinese companies, including Temu and the social media network TikTok.

The Pinduoduo suspension comes as lawmakers in Congress this week are gearing up to grill the CEO of TikTok over national security concerns. TikTok, which is owned by Beijing-based ByteDance, said last month that it now has roughly 150 million monthly active users in the United States.

A new cybersecurity strategy released earlier this month by the Biden administration singled out China as the greatest cyber threat to the U.S. and Western interests. The strategy says China now presents the “broadest, most active, and most persistent threat to both government and private sector networks,” and says China is “the only country with both the intent to reshape the international order and, increasingly, the economic, diplomatic, military, and technological power to do so.”

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