Interesting research: “EvilModel: Hiding Malware Inside of Neural Network Models.”
Abstract: Delivering malware covertly and detection-evadingly is critical to advanced malware campaigns. In this paper, we present a method that delivers malware covertly and detection-evadingly through neural network models. Neural network models are poorly explainable and have a good generalization ability. By embedding malware into the neurons, malware can be delivered covertly with minor or even no impact on the performance of neural networks. Meanwhile, since the structure of the neural network models remains unchanged, they can pass the security scan of antivirus engines. Experiments show that 36.9MB of malware can be embedded into a 178MB-AlexNet model within 1% accuracy loss, and no suspicious are raised by antivirus engines in VirusTotal, which verifies the feasibility of this method. With the widespread application of artificial intelligence, utilizing neural networks becomes a forwarding trend of malware. We hope this work could provide a referenceable scenario for the defense on neural network-assisted attacks.
Posted on July 27, 2021 at 6:25 AM •
ArsTechnica has a good story on the REvil ransomware attack of last weekend, with technical details:
This weekend’s attack was carried out with almost surgical precision. According to Cybereason, the REvil affiliates first gained access to targeted environments and then used the zero-day in the Kaseya Agent Monitor to gain administrative control over the target’s network. After writing a base-64-encoded payload to a file named agent.crt the dropper executed it.
The ransomware dropper Agent.exe is signed with a Windows-trusted certificate that uses the registrant name “PB03 TRANSPORT LTD.” By digitally signing their malware, attackers are able to suppress many security warnings that would otherwise appear when it’s being installed. Cybereason said that the certificate appears to have been used exclusively by REvil malware that was deployed during this attack.
To add stealth, the attackers used a technique called DLL Side-Loading, which places a spoofed malicious DLL file in a Windows’ WinSxS directory so that the operating system loads the spoof instead of the legitimate file. In the case here, Agent.exe drops an outdated version that is vulnerable to DLL Side-Loading of “msmpeng.exe,” which is the file for the Windows Defender executable.
Once executed, the malware changes the firewall settings to allow local windows systems to be discovered. Then, it starts to encrypt the files on the system….
REvil is demanding $70 million for a universal decryptor that will recover the data from the 1,500 affected Kaseya customers.
Note that this is yet another supply-chain attack. Instead of infecting those 1,500 networks directly, REvil infected a single managed service provider. And it leveraged a zero-day vulnerability in that provider.
EDITED TO ADD (7/13): Employees warned Kaseya’s management for years about critical security flaws, but they were ignored.
Posted on July 8, 2021 at 10:06 AM •
Two reports this week. The first is from Microsoft, which wrote:
As part of our investigation into this ongoing activity, we also detected information-stealing malware on a machine belonging to one of our customer support agents with access to basic account information for a small number of our customers. The actor used this information in some cases to launch highly-targeted attacks as part of their broader campaign.
The second is from the NSA, CISA, FBI, and the UK’s NCSC, which wrote that the GRU is continuing to conduct brute-force password guessing attacks around the world, and is in some cases successful. From the NSA press release:
Once valid credentials were discovered, the GTsSS combined them with various publicly known vulnerabilities to gain further access into victim networks. This, along with various techniques also detailed in the advisory, allowed the actors to evade defenses and collect and exfiltrate various information in the networks, including mailboxes.
Posted on July 2, 2021 at 6:26 AM •
Wired is reporting on a company called Mollitiam Industries:
Marketing materials left exposed online by a third-party claim Mollitiam’s interception products, dubbed “Invisible Man” and “Night Crawler,” are capable of remotely accessing a target’s files, location, and covertly turning on a device’s camera and microphone. Its spyware is also said to be equipped with a keylogger, which means every keystroke made on an infected device—including passwords, search queries and messages sent via encrypted messaging apps—can be tracked and monitored.
To evade detection, the malware makes use of the company’s so-called “invisible low stealth technology” and its Android product is advertised as having “low data and battery consumption” to prevent people from suspecting their phone or tablet has been infected. Mollitiam is also currently marketing a tool that it claims enables “mass surveillance of digital profiles and identities” across social media and the dark web.
Posted on June 23, 2021 at 6:01 AM •
Apostle seems to be a new strain of malware that destroys data.
In a post published Tuesday, SentinelOne researchers said they assessed with high confidence that based on the code and the servers Apostle reported to, the malware was being used by a newly discovered group with ties to the Iranian government. While a ransomware note the researchers recovered suggested that Apostle had been used against a critical facility in the United Arab Emirates, the primary target was Israel.
Posted on May 26, 2021 at 9:33 AM •
This seems to be a new tactic:
Emsisoft has identified two distinct tactics. In the first, hackers encrypt data with ransomware A and then re-encrypt that data with ransomware B. The other path involves what Emsisoft calls a “side-by-side encryption” attack, in which attacks encrypt some of an organization’s systems with ransomware A and others with ransomware B. In that case, data is only encrypted once, but a victim would need both decryption keys to unlock everything. The researchers also note that in this side-by-side scenario, attackers take steps to make the two distinct strains of ransomware look as similar as possible, so it’s more difficult for incident responders to sort out what’s going on.
Posted on May 21, 2021 at 8:50 AM •
Bizarro is a new banking trojan that is stealing financial information and crypto wallets.
…the program can be delivered in a couple of ways—either via malicious links contained within spam emails, or through a trojanized app. Using these sneaky methods, trojan operators will implant the malware onto a target device, where it will install a sophisticated backdoor that “contains more than 100 commands and allows the attackers to steal online banking account credentials,” the researchers write.
The backdoor has numerous commands built in to allow manipulation of a targeted individual, including keystroke loggers that allow for harvesting of personal login information. In some instances, the malware can allow criminals to commandeer a victim’s crypto wallet, too.
Posted on May 20, 2021 at 9:13 AM •
A lot of Russian malware—the malware that targeted the Colonial Pipeline, for example—won’t install on computers with a Cyrillic keyboard installed. Brian Krebs wonders if this could be a useful defense:
In Russia, for example, authorities there generally will not initiate a cybercrime investigation against one of their own unless a company or individual within the country’s borders files an official complaint as a victim. Ensuring that no affiliates can produce victims in their own countries is the easiest way for these criminals to stay off the radar of domestic law enforcement agencies.
DarkSide, like a great many other malware strains, has a hard-coded do-not-install list of countries which are the principal members of the Commonwealth of Independent States (CIS)—former Soviet satellites that mostly have favorable relations with the Kremlin.
Simply put, countless malware strains will check for the presence of one of these languages on the system, and if they’re detected the malware will exit and fail to install.
Will installing one of these languages keep your Windows computer safe from all malware? Absolutely not. There is plenty of malware that doesn’t care where in the world you are. And there is no substitute for adopting a defense-in-depth posture, and avoiding risky behaviors online.
But is there really a downside to taking this simple, free, prophylactic approach? None that I can see, other than perhaps a sinking feeling of capitulation. The worst that could happen is that you accidentally toggle the language settings and all your menu options are in Russian.
EDITED TO ADD (6/14): According to some, this doesn’t work.
Posted on May 18, 2021 at 10:31 AM •
Apple just patched a MacOS vulnerability that bypassed malware checks.
The flaw is akin to a front entrance that’s barred and bolted effectively, but with a cat door at the bottom that you can easily toss a bomb through. Apple mistakenly assumed that applications will always have certain specific attributes. Owens discovered that if he made an application that was really just a script—code that tells another program what do rather than doing it itself—and didn’t include a standard application metadata file called “info.plist,” he could silently run the app on any Mac. The operating system wouldn’t even give its most basic prompt: “This is an application downloaded from the Internet. Are you sure you want to open it?”
Posted on April 30, 2021 at 7:38 AM •
Most troublingly, Activision says that the “cheat” tool has been advertised multiple times on a popular cheating forum under the title “new COD hack.” (Gamers looking to flout the rules will typically go to such forums to find new ways to do so.) While the report doesn’t mention which forum they were posted on (that certainly would’ve been helpful), it does say that these offerings have popped up a number of times. They have also been seen advertised in YouTube videos, where instructions were provided on how gamers can run the “cheats” on their devices, and the report says that “comments [on the videos] seemingly indicate people had downloaded and attempted to use the tool.”
Part of the reason this attack could work so well is that game cheats typically require a user to disable key security features that would otherwise keep a malicious program out of their system. The hacker is basically getting the victim to do their own work for them.
“It is common practice when configuring a cheat program to run it the with the highest system privileges,” the report notes. “Guides for cheats will typically ask users to disable or uninstall antivirus software and host firewalls, disable kernel code signing, etc.”
Posted on April 2, 2021 at 6:00 AM •
Sidebar photo of Bruce Schneier by Joe MacInnis.