The U.S. Cybersecurity and Infrastructure Security Agency (CISA) this week released five new analysis reports detailing malware discovered on compromised Pulse Secure devices.
Adversaries have been targeting Pulse Connect Secure VPN appliances to exploit various vulnerabilities, including a couple of security holes discovered earlier this year, specifically CVE-2021-22893 and CVE-2021-22937.
In April this year, CISA released an alert on attacks targeting Pulse Secure devices, complemented with indicators of compromise (IOCs) and information on the malware used by attackers, and this week the agency published details on five additional malware samples.
Two of the samples, CISA reveals, are maliciously modified Pulse Secure files retrieved from infected devices, both of which function as credential harvesters. One of the files also acts as a backdoor, providing attackers with remote access to the compromised device.
Another file contained a malicious shell script that could log usernames and passwords. A third sample involved multiple files, including some consisting of a shell script that would modify a Pulse Secure file to become a webshell. One file was designed to intercept certificate-based multi-factor authentication, while others would parse incoming web request data.
The fifth sample consisted of two Perl scripts designed to execute attacker commands, a Perl library, a Perl script, and a shell script designed to manipulate and execute the ‘/bin/umount’ file.
CISA’s five malware analysis reports (MARs) include details on the tactics, techniques, and procedures (TTPs) employed by adversaries, as well as IOCs. The agency encourages users and administrators to review the provided information, as well as previously published alerts.
Pulse Secure, which was acquired last year by Ivanti, has released a tool that helps customers identify compromised appliances.
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