Malicious PDF — malware analysis report

Static analysis result for SHA-256 c900eb40f9a6c377…

MALICIOUS

PDF

84.3 KB Created: 2021-07-13 01:26:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: 34dd0c01d186a58975e6ba62abb52942 SHA-1: e28f502efc5c8074bc351710fa06a93f363cfcf4 SHA-256: c900eb40f9a6c37782cf1f6c3d66bf9c4b8b1f0686772df67a4bca27b411574e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV as a phishing trojan and by an ML classifier with high confidence. It contains numerous external URLs, many hosted on compromised CMS platforms or disposable domains, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true intent but reinforcing the malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://oniceh.ru/uplcv?utm_term=how+to+download+paid+books PDF link annotation
    • https://macleanpinesdrivingschool.com.au/wp-content/plugins/super-forms/uploads/php/files/041fdc79a5adf5737e9956e78d1ea39d/ranirabadonawopibag.pdfIn PDF document text
    • http://karpatskiles.ru/store/files/vuvize.pdfIn PDF document text
    • https://gotoko.com/cmsv2/upload/files/juvenenowanimirogaz.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/1607e5dfd1579b---37246834401.pdfIn PDF document text
    • http://farmaciafici.com/userfiles/files/muzudebisimirenol.pdfIn PDF document text
    • https://smithsgame.com/calisma2/files/uploads/reverisujavujapojoluli.pdfIn PDF document text
    • https://hurtowniaroza.pl/upload/files/65922486835.pdfIn PDF document text
    • http://2ds-creations.fr/userfiles/file/11203458049.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087880cade07---40576041586.pdfIn PDF document text
    • http://sjar-tech.com/uploadfile/file///2021060706294238.pdfIn PDF document text
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160afb4507cac7---womiwubo.pdfIn PDF document text
    • https://brandonsmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/6qlgvcv3qhkv56bqujccjanr62/27760683178.pdfIn PDF document text
    • http://jorkurojus.com/userfiles/file/temikukawixagetit.pdfIn PDF document text
    • https://militarynetwork.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1606d9ec4e5c7f---13902545895.pdfIn PDF document text
    • http://training-solutions.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1606faad722857---46563754127.pdfIn PDF document text
    • http://vetcarefoundation.org/userfiles/file/wekukapam.pdfIn PDF document text
    • http://forter.vn/hinhanh/file/xenubegijujoj.pdfIn PDF document text
    • http://scissortailfarms.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087153138246---wijamiwim.pdfIn PDF document text
    • http://manufim.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/16089011167b37---zimodolesanigutonu.pdfIn PDF document text
    • http://fultonhighschoolclassof1977.com/clients/a/ad/adf64365ba34d951c098eb677b062caf/File/43920357212.pdfIn PDF document text
    • http://trainternational.in/wp-content/plugins/formcraft/file-upload/server/content/files/1607517087531b---80671023758.pdfIn PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ce3c325b307---vojaronotabagusawosuvo.pdfIn PDF document text
    • http://xn----8sbxab3abskk3a2j.xn--p1ai/media/file/72793690991.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_off0000e6d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6D1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fee3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEE3 17544 bytes
SHA-256: bd249bbc95717ad983a87ff1d091385603e2fefa7b2f3808fd51897a110904e0
font_02_sfnt_off00012ca7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12CA7 10460 bytes
SHA-256: 18167eee876ca137fd94f3ad4168b5c91c803c979e84eba0c8a4d3ba698525d3