Unfolding Agent Tesla: The Art of Credentials Harvesting. Dropper Analysis By Osama Ellahi Published: 2024-08-15 · Archived: 2026-04-05 14:20:07 UTC Analysis of Agent Tesla, A Close Look at Password Theft Technique — Part — 1 — Dropper Analysis Executive Summary Agent Tesla is a very detailed form of malware that typically infiltrates systems through deceptive emails. Once executed, it goes through multiple stages, using various droppers to disguise its presence. The malware’s primary goal is to steal sensitive information, such as passwords, from web browsers, email, VPN, and FTP clients. It then secretly transmits this stolen data to the attacker’s email through a compromised email server. This highlights the importance of being cautious with email attachments to prevent falling victim to such malicious activities. Malware Flow Agent Tesla starts its malicious journey through a phishing email. The initial carrier is an {EXE} file, known as the dropper. Inside this executable file, there is a second stage {DLL} that gets loaded into its modules. Subsequently, a third stage {DLL} is loaded, followed by a fourth stage {DLL}. This fourth {DLL} is crucial, as it contains the actual Agent Tesla binary, which is also an {EXE} file. Upon execution, this fourth-stage binary extracts the Agent Tesla payload, decrypts it, and injects the Agent Tesla binary into its own running process. In simpler terms, it activates the malicious code within itself. The final stage binary is responsible for harvesting credentials from various sources, including browsers, email clients, VPN clients, and FTP clients. Once it successfully collects passwords from the system, the malware takes the next step by sending this stolen data to the attacker’s email address. To achieve this, it utilizes a compromised email server, completing the malicious cycle initiated by the phishing email. https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-f1a988cfd137 Page 1 of 3 | | To read this full blog click on following link. We shifted this blog to personal blogging website. https://breachnova.com/blog.php?id=29 | Get Osama Ellahi’s stories in your inbox Join Medium for free to get updates from this writer. Remember me for faster sign in | | Parts https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-f1a988cfd137 Page 2 of 3 Part — 1 — Dropper Analysis https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-f1a988cfd137 Part — 2 — Browsers Stealing https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-2d565c68db0d Part — 3- Discovery & Exfiltration https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-7a77f69435ee Part — 4 — Stealing FileZilla https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-d30da9c36988 Part — 5 — Stealing The BAT! EMAIL CLIENT https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-c3fe4854775b Part — 6 — Stealing Outlook Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-de3737f9d66e Part — 7 — Stealing Trillian Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-afa2dd6e9de7 Part — 8 — Stealing MailBird Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-e5501af1c942 Part — 9 — Stealing WinSCP Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-55e7b2c64d60 Part — 10 — Stealing Core FTP LE Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-cdce40f6a747 Part — 11 — Stealing WinSCP Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-db9bb6698041 Part — 12 — Stealing FTP Navigator Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-59818a3686a3 Part — 13 — Stealing FTP Commander Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-7d01a41d554b Part — 14 — Stealing FTP Getter Credentials https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-fe5ff29cc93c Source: https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-f1a988cfd137 https://osamaellahi.medium.com/unfolding-agent-tesla-the-art-of-credentials-harvesting-f1a988cfd137 Page 3 of 3