11 Malicious PyPI Python Libraries Caught Stealing Discord Tokens and Installing Shells

Cybersecurity researchers have uncovered as many as 11 malicious
Python packages that have been cumulatively downloaded more than
41,000 times from the Python Package Index (PyPI) repository, and
could be exploited to steal Discord access tokens, passwords, and
even stage dependency confusion attacks.

The Python packages have since been removed from the repository
following responsible disclosure by DevOps firm JFrog —

• importantpackage / important-package
• pptest
• ipboards
• owlmoon
• DiscordSafety
• trrfab
• 10Cent10 / 10Cent11
• yandex-yt
• yiffparty

Two of the packages (“importantpackage,” “10Cent10,” and their
variants) were found obtaining a reverse shell on the compromised
machine, giving the attacker full control over an infected machine.
Two other packages “ipboards” and “trrfab” masqueraded as
legitimate dependencies designed to be automatically imported by
taking advantage of a technique called dependency confusion^[1]
or namespace confusion.

Unlike typosquatting attacks, where a malicious actor
deliberately publishes packages with misspelled names of popular
variants, dependency confusion^[2]
works by uploading poisoned components with names that are the same
as the legitimate ones to public repositories, but with a higher
version, effectively forcing the target’s package manager to
download and install the malicious module.

The dependency “importantpackage” also stands out for its novel
exfiltration mechanism to evade network-based detection, which
involves using Fastly’s content delivery network (CDN) to mask its
communications with the attacker-controlled server as communication
with pypi[.]org.

The malicious code “causes an HTTPS request to be sent to
pypi.python[.]org (which is indistinguishable from a legitimate
request to PyPI), which later gets rerouted by the CDN as an HTTP
request to the [command-and-control] server,” JFrog researchers
Andrey Polkovnychenko and Shachar Menashe explained^[3]
in a report published Thursday.

Lastly, both “ipboards” and a fifth package named “pptest” were
discovered using DNS tunneling^[4]
as a data exfiltration method by relying on DNS requests as a
channel for communication between the victim machine and the remote
server.

Efforts to target popular code registries like Node Package
Manager (NPM) JavaScript registry, PyPI, and RubyGems have become
commonplace and a new frontier for an array of attacks.

“Package managers are a growing and powerful vector for the
unintentional installation of malicious code, and […] attackers are
getting more sophisticated in their approach,” said Menashe,
JFrog’s senior director of research. “The advanced evasion
techniques used in these malware packages, such as novel
exfiltration or even DNS tunneling signal a disturbing trend that
attackers are becoming stealthier in their attacks on open-source
software.”

Indeed, after at least three NPM developer accounts were
compromised by bad actors to insert malicious code into popular
packages “ua-parser-js^[5],” “coa,^[6]” and^[7]
“rc,” GitHub earlier
this week outlined^[8]
plans to tighten the security of the NPM registry by requiring
two-factor authentication (2FA) for maintainers and admins starting
in the first quarter of 2022.

The development also comes as the software development and
version control platform disclosed that it addressed multiple flaws
in the NPM registry that could have leaked the names of private
packages and allowed attackers to bypass authentication and publish
versions of any package without requiring any authorization.