Malicious PDF — malware analysis report

Static analysis result for SHA-256 858776f1a2b3a82e…

MALICIOUS

PDF

72.4 KB Created: 2021-07-10 05:09:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 520b938b3f817a1d7c17acefefcf6c7c SHA-1: 39bf47c96df1f5ad48a3a853a5e810a70f0d9ff9 SHA-256: 858776f1a2b3a82e74967e6e0f29cbc4754853a224f4c7cbdd005fb41aa474fc
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. Although no scripts were explicitly extracted, the nature of the URLs and the heuristic firings point towards a phishing or malware distribution attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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=access+of+symmetry+equation
    • http://sostrevalli.it/userfiles/files/56014996352.pdf
    • http://blevy.com/ckfinder/userfiles/files/56667966643.pdf
    • http://speakingaboutnetworking.com/ckfinder/userfiles/files/70117895622.pdf
    • http://jyjwqj.com/uploadfile/file///2021052407173773.pdf
    • https://baoholaodong24.com/userfiles/file/wemuxofi.pdf
    • https://trucraftsmanship.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a1ed2d0308e---54779124559.pdf
    • https://freedomhypnosisnyc.com/wp-content/plugins/super-forms/uploads/php/files/05c0b13a04abb29dd2e2bda1184969b5/18400969710.pdf
    • http://ophtalmic-overnight.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16099a46292152---duwagozige.pdf
    • http://usmleworkout.com/files/file/69109322970.pdf
    • https://hinodanang.com/uploads/image/files/tugegaxabelu.pdf
    • https://www.qlsny.com/wp-content/plugins/super-forms/uploads/php/files/04113ed5b8a17123c889938942d78949/18937708192.pdf
    • https://www.alarisusallc.com/wp-content/plugins/super-forms/uploads/php/files/acb30ff4ef2d2504e569f6ca0d2e6510/mogubilebexapevelodu.pdf
    • http://juniorsmagazine.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073e298d05e8---wuzederigomixatige.pdf
    • https://www.sesc.com.ua/wp-content/plugins/super-forms/uploads/php/files/209u1vacer6km0q48d9s1q0q11/15929407572.pdf
    • http://fondationmonetoile.org/clients/0/0e/0ecfe6182781ff486fe5156d2e85c11d/File/refuvolefonepodegir.pdf
    • https://www.reachcast.ca/wp-content/plugins/super-forms/uploads/php/files/6facf287e8630898a53213959f91730c/dijemibaxubepajid.pdf
    • http://www.chicagoalphas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083a467a57e3---gowiwinewibebexibawud.pdf
    • https://fulzugaskozpont.hu/files/wevasuf.pdf
    • https://givemeit.ru/wp-content/plugins/super-forms/uploads/php/files/0f820503ee0c5e4e93cd7a32d71f406a/nowimadijevifutenani.pdf
    • https://afd.me.uk/wp-content/plugins/super-forms/uploads/php/files/13jsanvbqtvk71mqmi41165mcc/fedonadod.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b8eb.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB8EB 16792 bytes
font_01_sfnt_off0000d0fd.bin
139227f324542276cee7ed054107b14ed46e9b25d96a9f0b882a2e0568f0cb92
pdf-font-stream PDF embedded font (sfnt) at offset 0xD0FD 16636 bytes
font_02_sfnt_off0000fbce.bin
b59a996e12cb2f4a4cfaf142e44438eb6a9c34c0a2bdfd5e7a629c290071935b
pdf-font-stream PDF embedded font (sfnt) at offset 0xFBCE 10792 bytes