Entries Tagged "malware"

Page 5 of 49

Another Malware with Persistence

Here’s a piece of Chinese malware that infects SonicWall security appliances and survives firmware updates.

On Thursday, security firm Mandiant published a report that said threat actors with a suspected nexus to China were engaged in a campaign to maintain long-term persistence by running malware on unpatched SonicWall SMA appliances. The campaign was notable for the ability of the malware to remain on the devices even after its firmware received new firmware.

“The attackers put significant effort into the stability and persistence of their tooling,” Mandiant researchers Daniel Lee, Stephen Eckels, and Ben Read wrote. “This allows their access to the network to persist through firmware updates and maintain a foothold on the network through the SonicWall Device.”

To achieve this persistence, the malware checks for available firmware upgrades every 10 seconds. When an update becomes available, the malware copies the archived file for backup, unzips it, mounts it, and then copies the entire package of malicious files to it. The malware also adds a backdoor root user to the mounted file. Then, the malware rezips the file so it’s ready for installation.

“The technique is not especially sophisticated, but it does show considerable effort on the part of the attacker to understand the appliance update cycle, then develop and test a method for persistence,” the researchers wrote.

Posted on March 9, 2023 at 8:33 PM • View Comments

BlackLotus Malware Hijacks Windows Secure Boot Process

Researchers have discovered malware that “can hijack a computer’s boot process even when Secure Boot and other advanced protections are enabled and running on fully updated versions of Windows.”

Dubbed BlackLotus, the malware is what’s known as a UEFI bootkit. These sophisticated pieces of malware target the UEFI—short for Unified Extensible Firmware Interface—the low-level and complex chain of firmware responsible for booting up virtually every modern computer. As the mechanism that bridges a PC’s device firmware with its operating system, the UEFI is an OS in its own right. It’s located in an SPI-connected flash storage chip soldered onto the computer motherboard, making it difficult to inspect or patch. Previously discovered bootkits such as CosmicStrand, MosaicRegressor, and MoonBounce work by targeting the UEFI firmware stored in the flash storage chip. Others, including BlackLotus, target the software stored in the EFI system partition.

Because the UEFI is the first thing to run when a computer is turned on, it influences the OS, security apps, and all other software that follows. These traits make the UEFI the perfect place to launch malware. When successful, UEFI bootkits disable OS security mechanisms and ensure that a computer remains infected with stealthy malware that runs at the kernel mode or user mode, even after the operating system is reinstalled or a hard drive is replaced.

ESET has an analysis:

The number of UEFI vulnerabilities discovered in recent years and the failures in patching them or revoking vulnerable binaries within a reasonable time window hasn’t gone unnoticed by threat actors. As a result, the first publicly known UEFI bootkit bypassing the essential platform security feature—UEFI Secure Boot—is now a reality. In this blogpost we present the first public analysis of this UEFI bootkit, which is capable of running on even fully-up-to-date Windows 11 systems with UEFI Secure Boot enabled. Functionality of the bootkit and its individual features leads us to believe that we are dealing with a bootkit known as BlackLotus, the UEFI bootkit being sold on hacking forums for $5,000 since at least October 2022.

[…]

  • It’s capable of running on the latest, fully patched Windows 11 systems with UEFI Secure Boot enabled.
  • It exploits a more than one year old vulnerability (CVE-2022-21894) to bypass UEFI Secure Boot and set up persistence for the bootkit. This is the first publicly known, in-the-wild abuse of this vulnerability.
  • Although the vulnerability was fixed in Microsoft’s January 2022 update, its exploitation is still possible as the affected, validly signed binaries have still not been added to the UEFI revocation list. BlackLotus takes advantage of this, bringing its own copies of legitimate—but vulnerable—binaries to the system in order to exploit the vulnerability.
  • It’s capable of disabling OS security mechanisms such as BitLocker, HVCI, and Windows Defender.
  • Once installed, the bootkit’s main goal is to deploy a kernel driver (which, among other things, protects the bootkit from removal), and an HTTP downloader responsible for communication with the C&C and capable of loading additional user-mode or kernel-mode payloads.

This is impressive stuff.

Posted on March 8, 2023 at 6:11 AM • View Comments

Malware Delivered through Google Search

Criminals using Google search ads to deliver malware isn’t new, but Ars Technica declared that the problem has become much worse recently.

The surge is coming from numerous malware families, including AuroraStealer, IcedID, Meta Stealer, RedLine Stealer, Vidar, Formbook, and XLoader. In the past, these families typically relied on phishing and malicious spam that attached Microsoft Word documents with booby-trapped macros. Over the past month, Google Ads has become the go-to place for criminals to spread their malicious wares that are disguised as legitimate downloads by impersonating brands such as Adobe Reader, Gimp, Microsoft Teams, OBS, Slack, Tor, and Thunderbird.

[…]

It’s clear that despite all the progress Google has made filtering malicious sites out of returned ads and search results over the past couple decades, criminals have found ways to strike back. These criminals excel at finding the latest techniques to counter the filtering. As soon as Google devises a way to block them, the criminals figure out new ways to circumvent those protections.

Posted on February 7, 2023 at 7:23 AM • View Comments

ChatGPT-Written Malware

I don’t know how much of a thing this will end up being, but we are seeing ChatGPT-written malware in the wild.

…within a few weeks of ChatGPT going live, participants in cybercrime forums—­some with little or no coding experience­—were using it to write software and emails that could be used for espionage, ransomware, malicious spam, and other malicious tasks.

“It’s still too early to decide whether or not ChatGPT capabilities will become the new favorite tool for participants in the Dark Web,” company researchers wrote. “However, the cybercriminal community has already shown significant interest and are jumping into this latest trend to generate malicious code.”

Last month, one forum participant posted what they claimed was the first script they had written and credited the AI chatbot with providing a “nice [helping] hand to finish the script with a nice scope.”

The Python code combined various cryptographic functions, including code signing, encryption, and decryption. One part of the script generated a key using elliptic curve cryptography and the curve ed25519 for signing files. Another part used a hard-coded password to encrypt system files using the Blowfish and Twofish algorithms. A third used RSA keys and digital signatures, message signing, and the blake2 hash function to compare various files.

Check Point Research report.

ChatGPT-generated code isn’t that good, but it’s a start. And the technology will only get better. Where it matters here is that it gives less skilled hackers—script kiddies—new capabilities.

Posted on January 10, 2023 at 7:18 AM • View Comments

Trojaned Windows Installer Targets Ukraine

Mandiant is reporting on a trojaned Windows installer that targets Ukrainian users. The installer was left on various torrent sites, presumably ensnaring people downloading pirated copies of the operating system:

Mandiant uncovered a socially engineered supply chain operation focused on Ukrainian government entities that leveraged trojanized ISO files masquerading as legitimate Windows 10 Operating System installers. The trojanized ISOs were hosted on Ukrainian- and Russian-language torrent file sharing sites. Upon installation of the compromised software, the malware gathers information on the compromised system and exfiltrates it. At a subset of victims, additional tools are deployed to enable further intelligence gathering. In some instances, we discovered additional payloads that were likely deployed following initial reconnaissance including the STOWAWAY, BEACON, and SPAREPART backdoors.

One obvious solution would be for Microsoft to give the Ukrainians Windows licenses, so they don’t have to get their software from sketchy torrent sites.

Posted on December 20, 2022 at 7:30 AM • View Comments

Leaked Signing Keys Are Being Used to Sign Malware

A bunch of Android OEM signing keys have been leaked or stolen, and they are actively being used to sign malware.

Łukasz Siewierski, a member of Google’s Android Security Team, has a post on the Android Partner Vulnerability Initiative (AVPI) issue tracker detailing leaked platform certificate keys that are actively being used to sign malware. The post is just a list of the keys, but running each one through APKMirror or Google’s VirusTotal site will put names to some of the compromised keys: Samsung, LG, and Mediatek are the heavy hitters on the list of leaked keys, along with some smaller OEMs like Revoview and Szroco, which makes Walmart’s Onn tablets.

This is a huge problem. The whole system of authentication rests on the assumption that signing keys are kept secret by the legitimate signers. Once that assumption is broken, all bets are off:

Samsung’s compromised key is used for everything: Samsung Pay, Bixby, Samsung Account, the phone app, and a million other things you can find on the 101 pages of results for that key. It would be possible to craft a malicious update for any one of these apps, and Android would be happy to install it overtop of the real app. Some of the updates are from today, indicating Samsung has still not changed the key.

Posted on December 8, 2022 at 7:08 AM • View Comments

CryWiper Data Wiper Targeting Russian Sites

Kaspersky is reporting on a data wiper masquerading as ransomware that is targeting local Russian government networks.

The Trojan corrupts any data that’s not vital for the functioning of the operating system. It doesn’t affect files with extensions .exe, .dll, .lnk, .sys or .msi, and ignores several system folders in the C:\Windows directory. The malware focuses on databases, archives, and user documents.

So far, our experts have seen only pinpoint attacks on targets in the Russian Federation. However, as usual, no one can guarantee that the same code won’t be used against other targets.

Nothing leading to an attribution.

News article.

Slashdot thread.

Posted on December 6, 2022 at 7:04 AM • View Comments

New Linux Cryptomining Malware

It’s pretty nasty:

The malware was dubbed “Shikitega” for its extensive use of the popular Shikata Ga Nai polymorphic encoder, which allows the malware to “mutate” its code to avoid detection. Shikitega alters its code each time it runs through one of several decoding loops that AT&T said each deliver multiple attacks, beginning with an ELF file that’s just 370 bytes.

Shikitega also downloads Mettle, a Metasploit interpreter that gives the attacker the ability to control attached webcams and includes a sniffer, multiple reverse shells, process control, shell command execution and additional abilities to control the affected system.

[…]

The final stage also establishes persistence, which Shikitega does by downloading and executing five shell scripts that configure a pair of cron jobs for the current user and a pair for the root user using crontab, which it can also install if not available.

Shikitega also uses cloud hosting solutions to store parts of its payload, which it further uses to obfuscate itself by contacting via IP address instead of domain name. “Without [a] domain name, it’s difficult to provide a complete list of indicators for detections since they are volatile and they will be used for legitimate purposes in a short period of time,” AT&T said.

Bottom line: Shikitega is a nasty piece of code. AT&T recommends Linux endpoint and IoT device managers keep security patches installed, keep EDR software up to date and make regular backups of essential systems.

Another article.

Slashdot thread.

Posted on September 12, 2022 at 9:41 AM • View Comments

Montenegro Is the Victim of a Cyberattack

Details are few, but Montenegro has suffered a cyberattack:

A combination of ransomware and distributed denial-of-service attacks, the onslaught disrupted government services and prompted the country’s electrical utility to switch to manual control.

[…]

But the attack against Montenegro’s infrastructure seemed more sustained and extensive, with targets including water supply systems, transportation services and online government services, among many others.

Government officials in the country of just over 600,000 people said certain government services remained temporarily disabled for security reasons and that the data of citizens and businesses were not endangered.

The Director of the Directorate for Information Security, Dusan Polovic, said 150 computers were infected with malware at a dozen state institutions and that the data of the Ministry of Public Administration was not permanently damaged. Polovic said some retail tax collection was affected.

Russia is being blamed, but I haven’t seen any evidence other than “they’re the obvious perpetrator.”

EDITED TO ADD (9/12): The Montenegro government is hedging on that Russia attribution. It seems to be a regular criminal ransomware attack. The Cuba Ransomware gang has Russian members, but that’s not the same thing as the government.

Posted on September 2, 2022 at 8:18 AM • View Comments

New UEFI Rootkit

Kaspersky is reporting on a new UEFI rootkit that survives reinstalling the operating system and replacing the hard drive. From an article:

The firmware compromises the UEFI, the low-level and highly opaque chain of firmware required to boot up nearly every modern computer. As the software that bridges a PC’s device firmware with its operating system, the UEFI—short for Unified Extensible Firmware Interface—is an OS in its own right. It’s located in an SPI-connected flash storage chip soldered onto the computer motherboard, making it difficult to inspect or patch the code. Because it’s the first thing to run when a computer is turned on, it influences the OS, security apps, and all other software that follows.

Both links have lots of technical details; the second contains a list of previously discovered UEFI rootkits. Also relevant are the NSA’s capabilities—now a decade old—in this area.

Posted on July 28, 2022 at 6:16 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.