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Rewterz penetration testing services help organizations determine if a cyber attacker can gain access to their critical assets while giving them detailed insights of the overall business impact of a cyber attack.
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September 22, 2023
Severity High Analysis Summary Ducktail Malware is a malicious program designed by hackers to infiltrate computers and networks globally. Ducktail malware is typically delivered through a […]September 22, 2023Severity Medium Analysis Summary First discovered in 2016, Revenge RAT is a remote access trojan (RAT) designed to give an attacker complete control over an infected […]September 22, 2023Severity High Analysis Summary The Konni APT (Advanced Persistent Threat) group is a cyber espionage group that has been active since at least 2014. It is […]Threat Insights
Before Rewterz got its start, the market was in dire need of a specialized and dedicated information security company. It was nearly impossible for businesses to find a trustworthy provider that could truly cover all of their bases. We wanted to meet this need, giving companies across the globe a chance to get ahead while knowing that their data is in good hands.
Connect with Us
Platform
Managed Security Services
Managed Penetration Testing
Rewterz penetration testing services help organizations determine if a cyber attacker can gain access to their critical assets while giving them detailed insights of the overall business impact of a cyber attack.
Resources
September 22, 2023Severity High Analysis Summary Ducktail Malware is a malicious program designed by hackers to infiltrate computers and networks globally. Ducktail malware is typically delivered through a […]September 22, 2023Severity Medium Analysis Summary First discovered in 2016, Revenge RAT is a remote access trojan (RAT) designed to give an attacker complete control over an infected […]September 22, 2023Severity High Analysis Summary The Konni APT (Advanced Persistent Threat) group is a cyber espionage group that has been active since at least 2014. It is […]Threat Insights
Before Rewterz got its start, the market was in dire need of a specialized and dedicated information security company. It was nearly impossible for businesses to find a trustworthy provider that could truly cover all of their bases. We wanted to meet this need, giving companies across the globe a chance to get ahead while knowing that their data is in good hands.
Connect with Us
Rewterz Threat Alert – New Zero Days in Zoom Allow Session Hijack
April 2, 2020Rewterz Threat Alert – DDG Mining Trojan and Botnet Attacking Linux Systems
April 2, 2020
Severity
High
Description
CVE-2012-0158 – This 8 years old remote code execution (or code injection) vulnerability in Microsoft Office is being currently exploited in a LimeRAT campaign. The bug enables an attacker to distribute read-only excel sheets to target victims with LimeRAT via malspam, in which they make use of a default password which excel first uses to decrypt contents of a file. When the hard-coded password is used, contents are decrypted in the background and users won’t be asked for a password. Malicious code will be executed without warning the user while the file appears benign in the read-only format.
Analysis Summary
A fresh campaign using Excel files to spread LimeRAT malware is found making use of the hardcoded, VelvetSweatshop default password for encrypted files. LimeRAT is a full-featured remote access tool/backdoor that can allow attackers to access an infected system and install a range of malware strains, like ransomware, cryptominers, keyloggers or botnet clients.
The new attackdeviates from conventional macro-based malware deliveryvia malspam. It sends malicious, encrypted Excel files using “read-only” mode so that users who are already aware of ‘enable-macros attack’ can be tricked into believing that there are no hidden macros in the file. The campaign makes use of the vulnerability leveraging the fact that to decrypt any given encrypted Excel file, Excel first tries to use an embedded, default password, “VelvetSweatshop,” to decrypt and open the file. At the same time, it keeps the file in read-only mode. Users are only required to enter a password when excel fails to decrypt a file with this default password. While this password is being used, in read-only mode, the app will thus eliminate the user interaction of providing a password. Using this encryption technique, attackers can bypass detection as well as suspicion by the user who will open the read-only file and macros will be executed without a warning.
Additionally, a blend of other techniques was also used in an attempt to fool anti-malware systems by encrypting the content of the spreadsheet hence hiding the exploit and payload. The hardcoded password is a well-known issue addressed in 2012 (CVE-2012-0158). Any type of malware is a good candidate for delivery using this new technique.
Impact
- Unauthorized Remote Access
- Detection Evasion
Remediation
- Do not download attachments from untrusted emails.
- Apart from macro-containing files, be wary of read-only files coming from untrusted sources as well.
- Keep endpoint security systems updated to bolster detection of malware loading or running on the host.