A Russian-linked threat group has been chaining a known WinRAR vulnerability to deploy a multi-stage malware pipeline targeting Ukrainian systems, according to research published by French cybersecurity firm Sekoia.
The group, tracked as Gamaredon — also known as Armageddon or UAC-0010 — is exploiting CVE-2025-8088, a path traversal flaw in the popular WinRAR archive utility. By crafting specially designed RAR files, the attackers are able to execute arbitrary payloads when a victim extracts the archive, bypassing the trust users typically place in seemingly routine file operations.
From Archive Extraction to Data Exfiltration
The attack chain begins with a weaponised archive file. When the target opens the RAR file, the path traversal vulnerability allows embedded files to be written to unintended locations on the system. This mechanism is used to drop an HTML Application (HTA) payload that Sekoia has dubbed GammaPhish.
GammaPhish serves as the initial staging component. Once executed, it connects to attacker-controlled infrastructure and retrieves additional malware modules — specifically GammaWorm and GammaSteel. GammaWorm is designed for propagation and persistence, enabling the malware to spread across connected systems, while GammaSteel focuses on data exfiltration, siphoning sensitive information from compromised machines.
The modular nature of this pipeline is notable. Rather than deploying a single monolithic backdoor, Gamaredon appears to have built a flexible framework where individual components can be selectively deployed depending on the target environment and mission objectives.
A Recurring Pattern
This is not the first time WinRAR has been weaponised in campaigns linked to Eastern European threat actors. In 2023, a separate path traversal flaw tracked as CVE-2023-38831 was widely exploited by multiple groups to deliver malware through booby-trapped archives. That vulnerability, which carried a CVSS score of 7.8, was similarly abused to execute malicious code when users opened seemingly benign ZIP or RAR files.
The recurrence of archive-based exploitation underscores a structural challenge in defensive security: file archiving utilities occupy a unique position in enterprise and personal computing workflows. Users routinely extract downloaded archives without suspicion, and security tools often grant greater leeway to such processes because they are fundamental, everyday operations. This makes path traversal vulnerabilities in archive utilities particularly dangerous — they turn a mundane user action into an execution vector.
Defenders Urged to Act
For security teams and system administrators, the discovery carries several immediate takeaways:
- Patch WinRAR promptly. CVE-2025-8088 has been addressed in newer releases, but unpatched installations remain vulnerable. Given WinRAR's massive installed base across enterprises and government agencies worldwide, delayed patching represents a significant risk window.
- Monitor for anomalous HTA execution. The use of HTA files as a staging mechanism is a well-known technique, but it remains effective when organisations do not actively monitor for
mshta.exespawning from unexpected parent processes. - Inspect suspicious process trees. Archive extraction utilities should not typically spawn script interpreters, network connections, or child processes that access user data directories. Behavioural detection rules flagging such activity can provide an early warning of exploitation.
- Restrict archive handling in high-risk environments. For organisations facing elevated targeting from state-sponsored actors, sandboxed or virtualised archive extraction can limit the blast radius of any exploit.
Gamaredon has long been one of the most persistent cyber threats facing Ukrainian infrastructure, with activity dating back years and escalating significantly since 2022. The group's continued refinement of its tooling — moving toward modular, selectively deployable malware families — suggests it is investing in long-term operational capability rather than relying on one-off campaigns.
The broader takeaway for the IT community is that archive utilities remain an underappreciated but highly attractive attack surface. Until the software ecosystem more thoroughly hardens these tools against path traversal and similar classes of vulnerability, exploitation of everyday file operations will continue to be a reliable vector for sophisticated adversaries.
根據法國網絡安全公司Sekoia發佈的研究，一個與俄羅斯有關的威脅組織，正在串連利用一個已知的WinRAR漏洞，部署多階段的惡意軟件流程，以烏克蘭系統為目標。
該組織被追蹤為Gamaredon——亦稱Armageddon或UAC-0010——正利用CVE-2025-8088，這是流行WinRAR歸檔工具中的一個路徑遍歷漏洞。攻擊者透過精心製作的RAR檔案，能夠在受害者解壓縮檔案時執行任意載荷，繞過用戶對看似常規檔案操作的信任。
從檔案解壓到資料外洩
攻擊鏈始於一個武器化的歸檔檔案。當目標開啟RAR檔案時，路徑遍歷漏洞允許嵌入的檔案被寫入系統上非預期的位置。此機制被用於投放一個HTML應用程式（HTA）載荷，Sekoia將其命名為 GammaPhish。
GammaPhish充當初始的暫存組件。一旦執行，它會連接到攻擊者控制的基礎設施，並檢索額外的惡意軟件模組——具體為 GammaWorm 和 GammaSteel。GammaWorm旨在進行傳播和維持持久性，使惡意軟件能在相連系統間擴散；而GammaSteel則專注於資料外洩，從受感染的機器中竊取敏感資訊。
此流程的模組化特性值得注意。Gamaredon似乎並非部署單一的單體後門，而是建立了一個靈活的框架，其中各個組件可根據目標環境和任務目標選擇性地部署。
重複出現的模式
這並非首次在與東歐威脅行為者相關的攻擊活動中看到WinRAR被武器化。2023年，一個名為CVE-2023-38831的獨立路徑遍歷漏洞被多個組織廣泛利用，透過藏有陷阱的歸檔檔案傳播惡意軟件。該漏洞的CVSS評分為7.8，同樣被濫用於在用戶開啟看似無害的ZIP或RAR檔案時執行惡意代碼。
基於歸檔檔案利用的情況反覆出現，凸顯了防禦性安全中的一個結構性挑戰：檔案歸檔工具在企業和個人電腦工作流程中佔據獨特位置。用戶經常在不加懷疑的情況下解壓縮下載的歸檔檔案，且安全工具通常對此類進程給予更大彈性，因為它們是基本的日常操作。這使得歸檔工具中的路徑遍歷漏洞尤其危險——它們將用戶的日常操作變成了執行向量。
呼籲防禦者採取行動
對於安全團隊和系統管理員，此發現帶來幾項即時要點：
- 立即為WinRAR打補丁。 CVE-2025-8088已在新版本中修復，但未安裝補丁的安裝仍然存在漏洞。鑑於WinRAR在全球企業和政府機構中巨大的安裝基礎，延遲打補丁代表著一個重要的風險窗口期。
- 監控異常的HTA執行。 使用HTA檔案作為暫存機制是一種眾所周知的技術，但當組織未積極監控
mshta.exe從非預期的父進程衍生時，它仍然有效。 - 檢查可疑的進程樹。 標準的歸檔解壓工具不應衍生腳本解釋器、網路連線或存取使用者資料目錄的子進程。將此類活動標記的行為偵測規則，可以提供漏洞利用的早期預警。
- 在高風險環境中限制歸檔處理。 對於面臨國家支持行為者高度針對性攻擊的組織，沙箱化或虛擬化的歸檔解壓可以限制任何漏洞利用的爆炸半徑。
Gamaredon長期以來一直是烏克蘭基礎設施面臨的最持久網絡威脅之一，其活動可追溯至多年前，並自2022年起顯著升級。該組織持續改進其工具——轉向模組化、可選擇性部署的惡意軟件家族——這表明其正在投資長期的作戰能力，而非依賴一次性活動。
對IT社群更廣泛的啟示是，歸檔工具仍然是一個未被充分重視但極具吸引力的攻擊面。在軟件生態系統更徹底地加固這些工具以抵禦路徑遍歷及類似漏洞之前，利用日常檔案操作將繼續成為複雜對手的可靠向量。