Malicious PDF — malware analysis report

Static analysis result for SHA-256 636cb7506748d86e…

MALICIOUS

PDF

91.2 KB Created: 2021-09-04 16:30:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 425a637e10f1076c16af342d3d3f66a4 SHA-1: 3cce7752b58c31b13b82c66d0bddc6450b3ec274 SHA-256: 636cb7506748d86ecfc94c4dbcf7233f352dda20c1b04726086388096b88dfe5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to multiple external URLs, some hosted on compromised CMS uploads. The PDF structure and embedded URLs suggest an attempt to lure users to potentially malicious sites for phishing or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9932

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 http://keifo.ru/ckfinder/userfiles/files/turokewetojovod.pdf In PDF document text
    • https://tramtron.vn/uploads/files/files/37856498068.pdfIn PDF document text
    • http://njnccualumni.com/clients/0/05/05b55d2c4c342460da0dc2f503861b12/File/wevubefuwuvoferapulabata.pdfIn PDF document text
    • https://mattweidnerlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d5c1d054162---41985484063.pdfIn PDF document text
    • https://dialogueinpraxis.net/files/docs/38570314176.pdfIn PDF document text
    • https://fullprotec.com/ckfinder/userfiles/files/29632037532.pdfIn PDF document text
    • http://visusmarble.com/images_upload/files/wokibum.pdfIn PDF document text
    • https://guclupin.com/calisma2/files/uploads/gituwonaluzibam.pdfIn PDF document text
    • http://kbinteriery.cz/userfiles/file/raxalawasugin.pdfIn PDF document text
    • https://www.varishastalari.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081eb50513be---36345294480.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/1609cf15c0ab1b---37863804778.pdfIn PDF document text
    • http://mama-care.com/UserFiles/file/11843311920.pdfIn PDF document text
    • http://mlkscholarshipsmilwaukee.org/clients/f/f0/f021f13c5c598389be7e913a1ae626ff/File/42184674562.pdfIn PDF document text
    • http://xatrbio.com/userfiles/file/jawelamepasajinemokelij.pdfIn PDF document text
    • http://boatmonies.com/uploads/files/worakoxogebibozokenawuga.pdfIn PDF document text
    • http://ambvetesopo.eu/userfiles/files/28193787078.pdfIn PDF document text
    • https://5a.ro/ckfinder/userfiles/files/tokisakakoliferefogu.pdfIn PDF document text
    • http://www.festivalmarrakech.info/wp-content/plugins/formcraft/file-upload/server/content/files/1609b0692d2bfe---65279102150.pdfIn PDF document text
    • http://sportsgarten.com/editorData/file/13105745967.pdfIn PDF document text
    • https://medtek.vn/storage/file/50648890310.pdfIn PDF document text
    • https://chezgregoire.fr/userfiles/10571150767.pdfIn PDF document text
    • https://marigabung.com/contents//files/73490638941.pdfIn PDF document text
    • http://refinerlink.com/userfiles/file/35093043540.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=s%C3%A1ch+th%C3%A1nh+kinh+d%C6%B0%E1%BB%A1ng+da+pdfPDF link annotation
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000db26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB26 29940 bytes
SHA-256: 4cc2cd1ca8c01e260f70cf489299ba673fdd70cef7220218c79a986c6d39d40b
font_01_sfnt_off0001150a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1150A 11156 bytes
SHA-256: 0b71cb35aac05994333352ecb2a6b8f36472217ff652188736b876f5f2bd2e7b
font_02_sfnt_off00012e4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E4D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off0001465e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1465E 16620 bytes
SHA-256: e617bec8a14d90ac714cfd665dcfae10292d0f36f4e10b7377e9a906ce57ab84

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