Entries Tagged "patching"

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Cobalt Strike Vulnerability Affects Botnet Servers

Cobalt Strike is a security tool, used by penetration testers to simulate network attackers. But it’s also used by attackers — from criminals to governments — to automate their own attacks. Researchers have found a vulnerability in the product.

The main components of the security tool are the Cobalt Strike client — also known as a Beacon — and the Cobalt Strike team server, which sends commands to infected computers and receives the data they exfiltrate. An attacker starts by spinning up a machine running Team Server that has been configured to use specific “malleability” customizations, such as how often the client is to report to the server or specific data to periodically send.

Then the attacker installs the client on a targeted machine after exploiting a vulnerability, tricking the user or gaining access by other means. From then on, the client will use those customizations to maintain persistent contact with the machine running the Team Server.

The link connecting the client to the server is called the web server thread, which handles communication between the two machines. Chief among the communications are “tasks” servers send to instruct clients to run a command, get a process list, or do other things. The client then responds with a “reply.”

Researchers at security firm SentinelOne recently found a critical bug in the Team Server that makes it easy to knock the server offline. The bug works by sending a server fake replies that “squeeze every bit of available memory from the C2’s web server thread….”

It’s a pretty serious vulnerability, and there’s already a patch available. But — and this is the interesting part — that patch is available to licensed users, which attackers often aren’t. It’ll be a while before that patch filters down to the pirated copies of the software, and that time window gives defenders an opportunity. They can simulate a Cobolt Strike client, and leverage this vulnerability to reply to servers with messages that cause the server to crash.

Posted on August 11, 2021 at 6:42 AMView Comments

Paragon: Yet Another Cyberweapons Arms Manufacturer

Forbes has the story:

Paragon’s product will also likely get spyware critics and surveillance experts alike rubbernecking: It claims to give police the power to remotely break into encrypted instant messaging communications, whether that’s WhatsApp, Signal, Facebook Messenger or Gmail, the industry sources said. One other spyware industry executive said it also promises to get longer-lasting access to a device, even when it’s rebooted.

[…]

Two industry sources said they believed Paragon was trying to set itself apart further by promising to get access to the instant messaging applications on a device, rather than taking complete control of everything on a phone. One of the sources said they understood that Paragon’s spyware exploits the protocols of end-to-end encrypted apps, meaning it would hack into messages via vulnerabilities in the core ways in which the software operates.

Read that last sentence again: Paragon uses unpatched zero-day exploits in the software to hack messaging apps.

Posted on August 3, 2021 at 6:44 AMView Comments

New Spectre-Like Attacks

There’s new research that demonstrates security vulnerabilities in all of the AMD and Intel chips with micro-op caches, including the ones that were specifically engineered to be resistant to the Spectre/Meltdown attacks of three years ago.

Details:

The new line of attacks exploits the micro-op cache: an on-chip structure that speeds up computing by storing simple commands and allowing the processor to fetch them quickly and early in the speculative execution process, as the team explains in a writeup from the University of Virginia. Even though the processor quickly realizes its mistake and does a U-turn to go down the right path, attackers can get at the private data while the processor is still heading in the wrong direction.

It seems really difficult to exploit these vulnerabilities. We’ll need some more analysis before we understand what we have to patch and how.

More news.

Posted on May 5, 2021 at 10:35 AMView Comments

Serious MacOS Vulnerability Patched

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?”

More.

Posted on April 30, 2021 at 7:38 AMView Comments

Accellion Supply Chain Hack

A vulnerability in the Accellion file-transfer program is being used by criminal groups to hack networks worldwide.

There’s much in the article about when Accellion knew about the vulnerability, when it alerted its customers, and when it patched its software.

The governor of New Zealand’s central bank, Adrian Orr, says Accellion failed to warn it after first learning in mid-December that the nearly 20-year-old FTA application — using antiquated technology and set for retirement — had been breached.

Despite having a patch available on Dec. 20, Accellion did not notify the bank in time to prevent its appliance from being breached five days later, the bank said.

CISA alert.

EDITED TO ADD (4/14): It appears spy plane details were leaked after the vendor didn’t pay the ransom.

Posted on March 23, 2021 at 6:32 AMView Comments

More on the Chinese Zero-Day Microsoft Exchange Hack

Nick Weaver has an excellent post on the Microsoft Exchange hack:

The investigative journalist Brian Krebs has produced a handy timeline of events and a few things stand out from the chronology. The attacker was first detected by one group on Jan. 5 and another on Jan. 6, and Microsoft acknowledged the problem immediately. During this time the attacker appeared to be relatively subtle, exploiting particular targets (although we generally lack insight into who was targeted). Microsoft determined on Feb. 18 that it would patch these vulnerabilities on the March 9th “Patch Tuesday” release of fixes.

Somehow, the threat actor either knew that the exploits would soon become worthless or simply guessed that they would. So, in late February, the attacker changed strategy. Instead of simply exploiting targeted Exchange servers, the attackers stepped up their pace considerably by targeting tens of thousands of servers to install the web shell, an exploit that allows attackers to have remote access to a system. Microsoft then released the patch with very little warning on Mar. 2, at which point the attacker simply sought to compromise almost every vulnerable Exchange server on the Internet. The result? Virtually every vulnerable mail server received the web shell as a backdoor for further exploitation, making the patch effectively useless against the Chinese attackers; almost all of the vulnerable systems were exploited before they were patched.

This is a rational strategy for any actor who doesn’t care about consequences. When a zero-day is confidential and undiscovered, the attacker tries to be careful, only using it on attackers of sufficient value. But if the attacker knows or has reason to believe their vulnerabilities may be patched, they will increase the pace of exploits and, once a patch is released, there is no reason to not try to exploit everything possible.

We know that Microsoft shares advance information about updates with some organizations. I have long believed that they give the NSA a few weeks’ notice to do basically what the Chinese did: use the exploit widely, because you don’t have to worry about losing the capability.

Estimates on the number of affected networks continues to rise. At least 30,000 in the US, and 100,000 worldwide. More?

And the vulnerabilities:

The Chinese actors were not using a single vulnerability but actually a sequence of four “zero-day” exploits. The first allowed an unauthorized user to basically tell the server “let me in, I’m the server” by tricking the server into contacting itself. After the unauthorized user gained entry, the hacker could use the second vulnerability, which used a malformed voicemail that, when interpreted by the server, allowed them to execute arbitrary commands. Two further vulnerabilities allow the attacker to write new files, which is a common primitive that attackers use to increase their access: An attacker uses a vulnerability to write a file and then uses the arbitrary command execution vulnerability to execute that file.

Using this access, the attackers could read anybody’s email or indeed take over the mail server completely. Critically, they would almost always do more, introducing a “web shell,” a program that would enable further remote exploitation even if the vulnerabilities are patched.

The details of that web shell matter. If it was sophisticated, it implies that the Chinese hackers were planning on installing it from the beginning of the operation. If it’s kind of slapdash, it implies a last-minute addition when they realized their exploit window was closing.

Now comes the criminal attacks. Any unpatched network is still vulnerable, and we know from history that lots of networks will remain vulnerable for a long time. Expect the ransomware gangs to weaponize this attack within days.

EDITED TO ADD (3/12): Right on schedule, criminal hacker groups are exploiting the vulnerabilities.

EDITED TO ADD (3/13): And now the ransomware.

Posted on March 10, 2021 at 6:28 AMView Comments

On Not Fixing Old Vulnerabilities

How is this even possible?

…26% of companies Positive Technologies tested were vulnerable to WannaCry, which was a threat years ago, and some even vulnerable to Heartbleed. “The most frequent vulnerabilities detected during automated assessment date back to 2013-­2017, which indicates a lack of recent software updates,” the reported stated.

26%!? One in four networks?

Even if we assume that the report is self-serving to the company that wrote it, and that the statistic is not generally representative, this is still a disaster. The number should be 0%.

WannaCry was a 2017 cyberattack, based on a NSA-discovered and Russia-stolen-and-published Windows vulnerability. It primarily affects older, no-longer-supported products like Windows 7. If we can’t keep our systems secure from these vulnerabilities, how are we ever going to secure them from new threats?

Posted on March 9, 2021 at 6:16 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.