Malicious PDF — malware analysis report

Static analysis result for SHA-256 9a40a44dd50967ae…

MALICIOUS

PDF

78.1 KB Created: 2021-09-16 13:33:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6c9813393740fd89cd393982e1427166 SHA-1: 275c14bbe588a37929704a9ac96b112901896269 SHA-256: 9a40a44dd50967ae5e0bc86449e9e07f8dc56e027178ea441d8785ba88cba304
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous embedded URLs, many of which are part of a link farm hosted on compromised or disposable domains. One embedded URL, https://krisoc.ru/uplcv?utm_term=pubg+mobile+lite+download+apk, suggests a lure related to game downloads. The presence of embedded JavaScript further indicates potential for malicious activity, such as exploiting vulnerabilities or redirecting users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://krisoc.ru/uplcv?utm_term=pubg+mobile+lite+download+apk PDF link annotation
    • http://abwalabamaave.com/uploads/files/90111340862.pdfIn PDF document text
    • http://alumcity.ru/userfiles/file/82105762229.pdfIn PDF document text
    • http://087334211.kad.tw/kads/ckfinder/userfiles/files/vikugivozagodusa.pdfIn PDF document text
    • http://pronobile.de/catalog/file/dadefepusake.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/a89bbdba55c7326365abdbc34b9a83b9/87029410596.pdfIn PDF document text
    • http://extreamtuning.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613af5a22b8d3---faxalalufilibeme.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613244a020adb---94665381258.pdfIn PDF document text
    • https://biorenta.lt/ckfinder/userfiles/files/6257983429.pdfIn PDF document text
    • http://hoshitorionline.com/uploads/files/fixigibipobewepin.pdfIn PDF document text
    • http://biosite.ru/images/news/file/lalotigesewu.pdfIn PDF document text
    • http://www.phonefixcomo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133c7b2d7e81---88203993213.pdfIn PDF document text
    • http://thanglong.vn-greenenergy.com/ckfinder/userfiles/files/67539361979.pdfIn PDF document text
    • http://architettoannalisatinelli.it/userfiles/files/91530093776.pdfIn PDF document text
    • https://k9-warrior.com/wp-content/plugins/super-forms/uploads/php/files/ahqc6je5ec0edhnqf5tf6thrvh/jasodad.pdfIn PDF document text
    • http://ortopediaszombathely.hu/editor_up/233347329.pdfIn PDF document text
    • http://banhangcongnghe.com/upload/FCK/file/28238754981.pdfIn PDF document text
    • https://bdblue.com/ckfinder/userfiles/files/57030921309.pdfIn PDF document text
    • https://imad0c0.com/js/ckfinder/userfiles/files/paporu.pdfIn PDF document text
    • https://femagnet.com/upload/edu/article/file/sumobepatavurixi.pdfIn PDF document text
    • http://tabouligrill.com/ckfinder/userfiles/files/25280292545.pdfIn PDF document text
    • http://hqshop24.com/userfiles/file/zizevokinogakat.pdfIn PDF document text
    • https://horgaszvelem.hu/ckfinder/userfiles/files/pujixajexefifido.pdfIn PDF document text
    • http://doradcyprawni.com/images/pliki/goxujanubawumaluvokajuwej.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c813.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC813 19436 bytes
SHA-256: 817af1884971b4e14bec3fc9453666796a85a289243b7454c4a3cdf0b13b8e88
font_01_sfnt_off0000fa10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA10 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011227.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11227 10888 bytes
SHA-256: 3bd32b283e34905b1def7a7cef503a2c9eefb731c63c3ee820bcc26615d4bee9

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