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Security advisories — Apr 20, 2021

Attacks Against Pulse Connect Secure (PCS) Appliances

2 minutes read
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THE THREAT

On April 20th, 2021, security services firm Mandiant released a report [1] detailing active attacks against Pulse Connect Secure (PCS) appliances. These attacks include using known vulnerabilities from 2019 and 2020 (CVE-2019-11510, CVE-2020-8243, and CVE-2020-8260) and a previously unknown authentication bypass vulnerability tracked as CVE-2021-22893. These attacks include bypassing both single and multi-factor authentication on the appliances and deployment of webshells for maintaining access.

Customers operating PCS appliances are strongly recommended to apply the relevant mitigation actions and utilize Pulse Secure’s Integrity Tool to assess impact.

What we’re doing about it

What you should do about it

Additional information

On April 20, 2021, Mandiant reported that previously known PCS vulnerabilities (CVE-2019-11510, CVE-2020-8243, CVE-2020-8260) and a zero-day (CVE-2021-22893) were exploited as early as August 2020, and some activity was still observed through March 2021. Pulse Secure notes that none of their other products were impacted by these issues.

Details on the zero-day vulnerability can be reviewed below:

Details on previously disclosed PCS vulnerabilities used in the attacks can be reviewed below:

Mandiant reported that twelve (12) malware families were used against organizations that were victim of the PCS attacks, including: ATRIUM, HARPULSE, LOCKPICK, PACEMAKER, PULSECHECK, PULSEJUMP, QUIETPULSE, RADIALPULSE, SLIGHTPULSE, SLOWPULSE, STEADYPULSE, and THINBLOOD. However, these malware variants were not all seen being used in conjunction, and some were seen in separate investigations, including malicious activities against the U.S Defense Industrial Base (DIB) networks, and other U.S. and European victim organizations such as defense, government, and finance. The main purpose of these malware tools was to circumvent authentication and to gain backdoor access.

At the time of writing, there is no indication that the backdoors were used in a supply chain attack on Pulse Secure’s software deployment process or network. In addition, the Pulse Secure team noted that they observed a limited number of customers impacted by exploitation of PCS appliances.

References:

[1] https://www.fireeye.com/blog/threat-research/2021/04/suspected-apt-actors-leverage-bypass-techniques-pulse-secure-zero-day.html
[2] https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44784/ (Workaround for CVE-2021-22893)
[3] https://kb.pulsesecure.net/articles/Pulse_Secure_Article/KB44755 (Integrity Tool Download)
[4] https://kb.pulsesecure.net/articles/Pulse_Secure_Article/KB44764 (Integrity Tool FAQ)
[5] https://blog.pulsesecure.net/pulse-connect-secure-security-update/
[6] https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44101/ (CVE-2019-11510)
[7] https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44588 (CVE-2020-8243)
[8] https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44601 (CVE-2020-8260)

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