{"id":4050,"date":"2025-05-18T10:04:02","date_gmt":"2025-05-18T10:04:02","guid":{"rendered":"https:\/\/serisec.com\/index.php\/2025\/05\/18\/pupkinstealer-attacks-windows-system-to-steal-login-credentials-desktop-files\/"},"modified":"2025-05-18T10:04:02","modified_gmt":"2025-05-18T10:04:02","slug":"pupkinstealer-attacks-windows-system-to-steal-login-credentials-desktop-files","status":"publish","type":"post","link":"https:\/\/serisec.com\/index.php\/2025\/05\/18\/pupkinstealer-attacks-windows-system-to-steal-login-credentials-desktop-files\/","title":{"rendered":"PupkinStealer Attacks Windows System to Steal Login Credentials & Desktop Files"},"content":{"rendered":"\n
PupkinStealer Attacks Windows System to Steal Login Credentials & Desktop Files<\/div>\n

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A new information-stealing malware dubbed \u201cPupkinStealer\u201d has been identified by cybersecurity researchers, targeting sensitive user data through a straightforward yet effective approach. <\/p>\n

First observed in April 2025, this .NET-based malware<\/a> written in C# focuses on stealing browser credentials, messaging app sessions, and desktop files, exfiltrating the data via Telegram\u2019s Bot API. <\/p>\n

Security experts note that PupkinStealer\u2019s simplicity and use of legitimate platforms for command-and-control operations make it a noteworthy threat, particularly as it lacks sophisticated anti-analysis features that would typically trigger security solutions.<\/p>\n

PupkinStealer operates as a lightweight 32-bit executable with a file size of just 6.21 MB, developed using the .NET framework and C#. Despite its relatively small footprint, the malware demonstrates significant data harvesting capabilities. <\/p>\n

PupkinStealer Attacks Windows System<\/strong><\/h2>\n

Security researchers have determined that PupkinStealer targets a specific range of sensitive information, including saved passwords and cookies from web browsers, session data from messaging platforms like Telegram and Discord, and select desktop files with specific extensions. <\/p>\n

Upon execution, the malware creates a compressed ZIP archive containing all stolen data, enriched with victim metadata including username, public IP address, and Windows Security<\/a> Identifier. <\/p>\n

The malware\u2019s design prioritizes compatibility across both x86 and x64 environments, using the Costura library to embed compressed DLLs.<\/p>\n

Unlike more sophisticated malware strains that employ extensive evasion techniques, PupkinStealer relies on straightforward execution methods and the absence of persistence mechanisms, suggesting a \u201chit-and-run\u201d approach designed to minimize detection during its brief operational window. <\/p>\n

The malware captures a 1920\u00d71080 JPG screenshot of the victim\u2019s desktop, providing attackers with additional contextual information about the compromised system. <\/p>\n

PupkinStealer\u2019s design indicates it was created for less-sophisticated threat actors, potentially distributed through malware-as-a-service (MaaS) models that enable rapid monetization through credential theft and data resale.<\/p>\n

PupkinStealer\u2019s use of Telegram\u2019s Bot API for command-and-control and data exfiltration represents a growing trend among cybercriminals who leverage legitimate platforms to blend malicious traffic with normal communications. <\/p>\n

According to security researchers, malware that uses Telegram as a C2 channel typically employs the Telegram Bot API for communications, allowing attackers to maintain control while hiding their activities within legitimate traffic patterns.<\/p>\n

Researchers have identified<\/a> a significant flaw in Telegram\u2019s Bot API that PupkinStealer exploits: all past bot messages can be replayed by an adversary capable of intercepting and decrypting HTTPS traffic. <\/p>\n

Unlike regular Telegram messages that use the platform\u2019s MTProto encryption, bot API communications are only protected by the HTTPS layer, creating a security vulnerability. <\/p>\n

The malware exfiltrates stolen data by sending the compressed archive to a Telegram bot via a crafted API URL, with captions detailing victim information and module success flags to enhance data processing efficiency. <\/p>\n

This approach enables attackers to evade traditional network monitoring solutions by hiding within traffic to a popular messaging platform.<\/p>\n

\u201cArdent\u201d Developer with Possible Russian Connections<\/strong><\/h2>\n

Cybersecurity researchers attribute PupkinStealer<\/a> to a developer known as \u201cArdent\u201d based on embedded code strings found during analysis. <\/p>\n

The presence of Russian-language text in the Telegram bot\u2019s metadata, including the term \u201ckanal\u201d (Russian for \u201cchannel\u201d), suggests possible Russian origins, although no definitive geographic targeting has been confirmed. <\/p>\n

This attribution information comes amid growing concerns about ransomware and information-stealing campaigns originating from Eastern European cybercriminal groups.<\/p>\n

The emergence of PupkinStealer highlights an evolving threat landscape where malware authors increasingly focus on simplicity and legitimate platform abuse rather than sophisticated technical features. <\/p>\n

Its focus on e-commerce related data, including browser credentials and financial platform sessions, poses significant risks to online retailers and their customers.<\/p>\n

Security experts recommend that organizations implement multi-factor authentication, regularly audit third-party application access to messaging platforms, and maintain robust endpoint protection<\/a> to defend against this emerging threat.<\/p>\n

As PupkinStealer demonstrates, modern malware no longer requires complex code to effectively steal sensitive information \u2013 sometimes the simplest approaches prove most difficult to detect.<\/p>\n

\n\n\n\n\n\n\n\n
Item<\/th>\nDetails<\/th>\n<\/tr>\n<\/thead>\n
Malware Sample<\/td>\nPupkinStealer<\/td>\n<\/tr>\n
Sample Hash<\/td>\n9309003c245f94ba4ee52098dadbaa0d0a4d83b423d76c1bfc082a1c29e0b95f<\/td>\n<\/tr>\n
Search Command<\/td>\n$ polyswarm link list -f PupkinStealer<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

Vulnerability Attack Simulation on How Hackers Rapidly Probe Websites for Entry Points \u2013\u00a0Free Webinar<\/a><\/strong><\/p>\n

The post PupkinStealer Attacks Windows System to Steal Login Credentials & Desktop Files<\/a> appeared first on Cyber Security News<\/a>.<\/p>\n<\/div>\n

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PupkinStealer Attacks Windows System to Steal Login Credentials & Desktop Files A new information-stealing malware dubbed \u201cPupkinStealer\u201d has been identified by cybersecurity researchers, targeting sensitive user data through a straightforward yet effective approach. First observed in April 2025, this .NET-based malware written in C# focuses on stealing browser credentials, messaging app sessions, and desktop files, […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[677,129,63,258,395],"tags":[130],"class_list":["post-4050","post","type-post","status-publish","format-standard","hentry","category-cyber-attack-article","category-cyber-security","category-cyber-security-news","category-malware","category-windows","tag-cyber-security-news"],"_links":{"self":[{"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/posts\/4050"}],"collection":[{"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/comments?post=4050"}],"version-history":[{"count":0,"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/posts\/4050\/revisions"}],"wp:attachment":[{"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/media?parent=4050"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/categories?post=4050"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/serisec.com\/index.php\/wp-json\/wp\/v2\/tags?post=4050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}