Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac21aaac31d22879…

MALICIOUS

PDF

80.9 KB Created: 2021-09-17 03:50:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 7e6f07bf68f7f042537b0f1e4ae53988 SHA-1: 06739d7a80ae377a6059fec3f1eb310b4887b4d0 SHA-256: ac21aaac31d228793e2056616b9222c3b69440a0cdade1c1a2ef6abd6343b2f4
156 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and link farm heuristics, indicating it's designed to redirect users to potentially malicious websites. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware delivery. The document body is unreadable, but the presence of compromised CMS upload links and SEO disposable link farms points to a deliberate effort to host and distribute malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://cructi.ru/uplcv?utm_term=bluestack+player+for+windows+8 PDF link annotation
    • https://k31szmq42-nu28.com/contents/files/rosolivurelatalikasuzuten.pdfIn PDF document text
    • http://186086.com/upload/files/96959971192.pdfIn PDF document text
    • http://jumpstart.mobi/ckfinder/userfiles/files/62081900112.pdfIn PDF document text
    • http://oasis-inwaste.asia/files/file/worixifepo.pdfIn PDF document text
    • https://eko-briketes.lv/userfiles/files/fimagaveteme.pdfIn PDF document text
    • https://earthchartercities.org/wp-content/plugins/formcraft/file-upload/server/content/files/161378f6468648---9490708727.pdfIn PDF document text
    • https://ooobelkom.ru/ckfinder/userfiles/files/punakijiwibowetujuda.pdfIn PDF document text
    • http://yksskj.com/ckfinder/userfiles/files/12575294586.pdfIn PDF document text
    • http://seksdagen.nl/userfiles/file/73946186631.pdfIn PDF document text
    • http://profil-metall.de/content/uploads/file/77953668139.pdfIn PDF document text
    • https://gamepinleri.com/calisma2/files/uploads/mobiti.pdfIn PDF document text
    • http://csc0351.com/userfiles/file/20210910065619_ycln6j.pdfIn PDF document text
    • http://hostingureitings.lv/uploads/userfiles/files/3003324213.pdfIn PDF document text
    • http://emeat.ru/var/files/lezirilivadeviwowi.pdfIn PDF document text
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/79834489998.pdfIn PDF document text
    • https://igruppe.no/ckfinder/userfiles/files/68164405310.pdfIn PDF document text
    • http://vikingpaint.com/user_file/file/57965503639.pdfIn PDF document text
    • https://nycsmindia.org/ckfinder/userfiles/files/14082123386.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/16141566f80907---4922588828.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141639a5154d---83344306810.pdfIn PDF document text
    • https://wct.goldcrownresort.com/magazine_files/files/dusupakatijabowukidowi.pdfIn PDF document text
    • http://perfectthesale.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142e17857da3---wiroxovubinoxuled.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_off0000d5cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5CD 17656 bytes
SHA-256: c0ea0b13840ba0f500fe49960827bfb72c027073a985472352d3d5fb0574ca9a
font_01_sfnt_off0001033b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1033B 11264 bytes
SHA-256: 19fffafa256aff6b54c0c0db8d58a3eaeaff9b3dcf2774499787e7a8b7693192
font_02_sfnt_off00011ded.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DED 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1