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APT32 state hackers target human rights defenders with spyware

Vietnam-linked APT32 group targeted Vietnamese human rights defenders (HRDs) between February 2018 and November 2020. Vietnam-linked APT32 (aka Ocean Lotus) group has conducted a cyberespionage campaign targeting Vietnamese human rights defenders (HRDs) and a nonprofit (NPO) human rights organization from Vietnam between February 2018 and November 2020. The threat actors used by spyware to take […]
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AA21-055A: Exploitation of Accellion File Transfer Appliance

Original release date: February 24, 2021SummaryThis joint advisory is the result of a collaborative effort by the cybersecurity authorities of Australia,[1] New Zealand,[2] Singapore,[3] the United Kingdom,[4] and the United States.[5][6] These authorities are aware of cyber actors exploiting vulnerabilities in Accellion File Transfer Appliance (FTA).[7] This activity has impacted organizations globally, including those in Australia, New Zealand, Singapore, the United Kingdom, and the United States.

Worldwide, actors have exploited the vulnerabilities to attack multiple federal and state, local, tribal, and territorial (SLTT) government organizations as well as private industry organizations including those in the medical, legal, telecommunications, finance, and energy sectors. According to Accellion, this activity involves attackers leveraging four vulnerabilities to target FTA customers.[8] In one incident, an attack on an SLTT organization potentially included the breach of confidential organizational data. In some instances observed, the attacker has subsequently extorted money from victim organizations to prevent public release of information exfiltrated from the Accellion appliance.

This Joint Cybersecurity Advisory provides indicators of compromise (IOCs) and recommended mitigations for this malicious activity. For a downloadable copy of IOCs, see: AA21-055A.stix and MAR-10325064-1.v1.stix.

Click here for a PDF version of this report.
Technical DetailsAccellion FTA is a file transfer application that is used to share files. In mid-December 2020, Accellion was made aware of a zero-day vulnerability in Accellion FTA and released a patch on December 23, 2020. Since then, Accellion has identified cyber actors targeting FTA customers by leveraging the following additional vulnerabilities.

CVE-2021-27101 – Structured Query Language (SQL) injection via a crafted HOST header (affects FTA 9_12_370 and earlier)
CVE-2021-27102 – Operating system command execution via a local web service call (affects FTA versions 9_12_411 and earlier)
CVE-2021-27103 – Server-side request forgery via a crafted POST request (affects FTA 9_12_411 and earlier)
CVE-2021-27104 – Operating system command execution via a crafted POST request (affects FTA 9_12_370 and earlier)

One of the exploited vulnerabilities (CVE-2021-27101) is an SQL injection vulnerability that allows an unauthenticated user to run remote commands on targeted devices. Actors have exploited this vulnerability to deploy a webshell on compromised systems. The webshell is located on the target system in the file /home/httpd/html/about.html or /home/seos/courier/about.html. The webshell allows the attacker to send commands to targeted devices, exfiltrate data, and clean up logs. The clean-up functionality of the webshell helps evade detection and analysis during post incident response. The Apache /var/opt/cache/rewrite.log file may also contain the following evidence of compromise:

[.’))union(select(c_value)from(t_global)where(t_global.c_param)=(‘w1′))] (1) pass through /courier/document_root.html
[.’))union(select(reverse(c_value))from(t_global)where(t_global.c_param)=(‘w1’))] (1) pass through /courier/document_root.html
[‘))union(select(loc_id)from(net1.servers)where(proximity)=(0))] (1) pass through /courier/document_root.html

These entries are followed shortly by a pass-through request to sftp_account_edit.php. The entries are the SQL injection attempt indicating an attempt at exploitation of the HTTP header parameter HTTP_HOST.

Apache access logging shows successful file listings and file exfiltration:

“GET /courier/about.html?aid=1000 HTTP/1.1” 200 {Response size}
“GET /courier/about.htmldwn={Encrypted Path}&fn={encrypted file name} HTTP/1.1” 200 {Response size}

When the clean-up function is run, it modifies archived Apache access logs /var/opt/apache/c1s1-access_log.*.gz and replaces the file contents with the following string:

      Binary file (standard input) matches

In two incidents, the Cybersecurity and Infrastructure Security Agency (CISA) observed a large amount of data transferred over port 443 from federal agency IP addresses to 194.88.104[.]24. In one incident, the Cyber Security Agency of Singapore observed multiple TCP sessions with IP address 45.135.229[.]179.

Organizations are encouraged to investigate the IOCs outlined in this advisory and in [AR21-055A]. If an Accellion FTA appears compromised, organizations can get an indication of the exfiltrated files by obtaining a list of file-last-accessed events for the target files of the symlinks located in the /home/seos/apps/1000/ folder over the period of malicious activity. This information is only indicative and may not be a comprehensive identifier of all exfiltrated files.
MitigationsOrganizations with Accellion FTA should:

Temporarily isolate or block internet access to and from systems hosting the software.
Assess the system for evidence of malicious activity including the IOCs, and obtain a snapshot or forensic disk image of the system for subsequent investigation.
If malicious activity is identified, obtain a snapshot or forensic disk image of the system for subsequent investigation, then:

Consider conducting an audit of Accellion FTA user accounts for any unauthorized changes, and consider resetting user passwords.
Reset any security tokens on the system, including the “W1” encryption token, which may have been exposed through SQL injection.

Update Accellion FTA to version FTA_9_12_432 or later.
Evaluate potential solutions for migration to a supported file-sharing platform after completing appropriate testing.

Accellion has announced that FTA will reach end-of-life (EOL) on April 30, 2021.[9] Replacing software and firmware/hardware before it reaches EOL significantly reduces risks and costs.

Additional general best practices include:

Deploying automated software update tools to ensure that third-party software on all systems is running the most recent security updates provided by the software vendor.
Only using up-to-date and trusted third-party components for the software developed by the organization.
Adding additional security controls to prevent the access from unauthenticated sources.

Resources

FireEye Blog – Cyber Criminals Exploit Accellion FTA for Data Theft and Extortion 

https://www.fireeye.com/blog/threat-research/2021/02/accellion-fta-exploited-for-data-theft-and-extortion.html 

Center for Internet Security (CIS) Critical Security Controls for Effective Cyber Defense, known as “CIS Controls” 

https://www.cisecurity.org/controls/
https://www.cisecurity.org/ms-isac/

Australia, Canada, New Zealand, the United Kingdom, and the United States Joint Advisory on Technical Approaches to Uncovering and Remediating Malicious Activity 

https://us-cert.cisa.gov/ncas/alerts/aa20-245a 

CISA and MS-ISAC’s Ransomware Guide 

https://www.cisa.gov/sites/default/files/publications/CISA_MS-ISAC_Ransomware%20Guide_S508C.pdf

References
[1] Australian Cyber Security Centre (ACSC) [2] New Zealand National Cyber Security Centre (NZ NCSC) [3] Singapore Cyber Security Agency (CSA) [4] United Kingdom National Cyber Security Centre (UK NCSC) [5] United States Cybersecurity and Infrastructure Security Agency (CISA) [6] United States Multi-State Information Sharing and Analysis Center (MS-ISAC) [7] Accellion Press Release: Update to Recent FTA Security Incident [8] Accellion Press Release: Update to Recent FTA Security Incident [9] Accellion Announcement: End-of-Life for Legacy FTA Software Revisions
February 24, 2021: Initial Version

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Bogus FedEx and DHL Phishbait

Researchers at Armorblox describe an ongoing phishing campaign that’s using phony FedEx and DHL shipping notifications as phishing lures.
“A few days ago, the Armorblox threat research team observed an email impersonating FedEx attempt to hit one of our customer environments,” the researchers write. “The email was titled ‘You have a new FedEx sent to you’ followed by the date the email was sent. The email contained some information about the document to make it seem legitimate, along with links to view the supposed document.”
The emails contained links to the Quip document hosting service, where the attackers had set up a landing page with a link to a spoofed Office 365 login page. The DHL phishing scam used a similar technique.
“The email sender name was ‘Dhl Express’ and title was ‘Your parcel has arrived’, including the victim’s email address at the end of the title,” Armorblox says. “The email informed victims that a parcel arrived for them at the post office, and that the parcel couldn’t be delivered due to incorrect delivery details. The email includes attached shipping documents that victims are guided to check if they want to receive their delivery.”
These emails contained an HTML attachment that opened what appeared to be a blurred-out spreadsheet behind an Adobe login box. The login overlay had the user’s email address pre-filled in the first box, so the researchers believe the attackers were trying to trick the user into entering their email password rather than their Adobe account credentials.
The researchers conclude that people should use a combination of training and technical defenses such as two-factor authentication to defend themselves against these attacks.
“Since we get so many emails from service providers, our brains have been trained to quickly execute on their requested actions,” they write. “It’s much easier said than done, but engage with these emails in a rational and methodical manner whenever possible. Subject the email to an eye test that includes inspecting the sender name, sender email address, language within the email, and any logical inconsistencies within the email (e.g. Why is the email sender name ‘Dhl Express’ instead of ‘DHL Express’, Why does this shipping details document have an HTML extension? etc.).”
What might users be trained to look for? Poor idiomatic control, for one thing. The logos and layouts are very nicely done, but the words are a bit clumsier: DHL and FedEx have better writers. New-school security awareness training can create a culture of security within your organization so your employees can recognize phishing and other types of social engineering attacks.
Armorblox has the story.