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`crossenv` malware on the npm registry

On August 1, a user notified us via Twitter that a package with a name very similar to the popular cross-env package was sending environment variables from its installation context out to We investigated this report immediately and took action to remove the package. Further investigation led us to remove about 40 packages in total.

On July 19 a user named hacktask published a number of packages with names very similar to some popular npm packages. We refer to this practice as “typo-squatting”. In the past, it’s been mostly accidental. In a few cases we’ve seen deliberate typo-squatting by authors of libraries that compete with existing packages. This time, the package naming was both deliberate and malicious—the intent was to collect useful data from tricked users.

All of hacktask’s packages have been removed from the npm registry.

Adam Baldwin of Lift Security also looked into this incident to see if there were any other packages, not owned by hacktask, with the same package setup code. He has every file in the public registry indexed by content hash to make scans like this possible. He did not find any other instances of that specific file with those contents.


Following is a list of hacktask’s packages, with a count of total downloads from 7/19 to 7/31.

Download counts for these packages are larger in the last two days because of public interest in the problem. The numbers from before exposure are more revealing of the effect of the malware. Note that 30-40 downloads is typical for any public package published to the registry, from registry mirrors automatically downloading copies. From this you can see that the real danger came from the crossenv package, which had nearly 700 downloads, with some secondary exposure from the jquery typosquats. But even in that case, most of the downloads come from mirrors requesting copies of the 16 versions of crossenv published. Our estimate is that there were at most 50 real installations of crossenv, probably fewer.

babelcli: 42
cross-env.js: 43
crossenv: 679
d3.js: 72
fabric-js: 46
ffmepg: 44
gruntcli: 67
http-proxy.js: 41
jquery.js: 136
mariadb: 92
mongose: 196
mssql-node: 46
mssql.js: 48
mysqljs: 77
node-fabric: 87
node-opencv: 94
node-opensl: 40
node-openssl: 29
node-sqlite: 61
node-tkinter: 39
nodecaffe: 40
nodefabric: 44
nodeffmpeg: 39
nodemailer-js: 40
nodemailer.js: 39
nodemssql: 44
noderequest: 40
nodesass: 66
nodesqlite: 45
opencv.js: 40
openssl.js: 43
proxy.js: 43
shadowsock: 40
smb: 40
sqlite.js: 48
sqliter: 45
sqlserver: 50
tkinter: 45

If you downloaded and installed any of these packages, you should immediately revoke and replace any credentials you might have had in your shell environment.

what we plan to do next

hacktask’s email address is banned from using npm. In this era of throwaway email addresses, that is not sufficient to prevent the human being behind it from trying again, but we felt it was a necessary gesture.

We are supporting ^Lift Security and the Node Security Project in their ongoing work to do static analysis of public registry packages, but this will not find every problem. Determining if a package contains malicious content when published is, of course, equivalent to the halting problem and therefore not something we can do.

We’re discussing various approaches to detecting and preventing publication—either accidental or malicious—of packages with names very close to existing packages. There are programmatic ways to detect this, and we might use them to block publication. We’re using the Smyte service to detect spam as it is published to the registry, and will be experimenting with using it to detect other kinds of violations of our terms of service.

Please do reach out to us immediately if you find malware on the registry. The best way to do so is by sending email to We will act to clean up the problem and find related problems if we can.