Malicious PDF — malware analysis report

Static analysis result for SHA-256 9855ec24aafb8c76…

MALICIOUS

PDF

74.9 KB Created: 2021-09-20 14:34:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 85f68ab82327f6ad8aa522b529ced1b4 SHA-1: 2be47b509867ed4833c53ce616f4fed3d28c8f89 SHA-256: 9855ec24aafb8c76c74c56abb4c7dc86491fabd8bde43cffcdcd18d29e804cd4
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous external URLs, several of which point to compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of multiple links on potentially compromised or disposable hosting suggests an attempt to obscure the final destination or evade detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://rrr71.ru/upload_picture/rewex.pdf In PDF document text
    • http://k-sta.kr/FileData/ckfinder/files/20210917_50F26A1E30B59DFB.pdfIn PDF document text
    • https://mai-avto.ru/upload_files/file/56176601567.pdfIn PDF document text
    • http://www.mustwalge.ee/data/content/files/jidumusikiwekevape.pdfIn PDF document text
    • https://www.higher-energy-trampolineclub.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134bebdeb55b---5763005191.pdfIn PDF document text
    • https://mysilo.com/upload/ckfinder/files/56297400346.pdfIn PDF document text
    • http://maekalocal.com/Maeka/UserFiles/File/lopusuxujawa.pdfIn PDF document text
    • http://maybaobidinhdinh.com/upload/files/29496149326.pdfIn PDF document text
    • https://greenboo.vn/uploads/files/60216832731.pdfIn PDF document text
    • http://studionegrelli.it/userfiles/files/45603561674.pdfIn PDF document text
    • https://bosingels.nl/ckfinder/userfiles/files/88064755973.pdfIn PDF document text
    • http://fratellibeninca.com/images/file/52310645290.pdfIn PDF document text
    • http://www.maarsehoveniers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16136ffe6cafe6---58271102738.pdfIn PDF document text
    • https://dallaslandscapedesign.com/media/files/7291972018.pdfIn PDF document text
    • http://landroverbh.com/ckfinder/userfiles/files/gunuluvivabezafewozor.pdfIn PDF document text
    • http://bbfrontedelmare.com/userfiles/files/73644185191.pdfIn PDF document text
    • http://pb-book.com/user_file/file/kesiremozujufi.pdfIn PDF document text
    • http://sandlnae.com/data/editor/file/velesepezowo.pdfIn PDF document text
    • https://takipbizde.com/calisma2/files/uploads/90819553173.pdfIn PDF document text
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132fdc460739---bemibosit.pdfIn PDF document text
    • http://sampleshipyard.com/userfiles/file/pedusevazebexasamefi.pdfIn PDF document text
    • https://at2-turbo-j3t.com/contents/files/dakabotufo.pdfIn PDF document text
    • http://chapelguild.com/images/usr/wopepudejisumejex.pdfIn PDF document text
    • http://trineckevzdelavani.cz/webpagebuilder/ckfinder/userfiles/files/32759498958.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=gallery+apps+without+adsPDF 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c1de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC1DE 16584 bytes
SHA-256: 0e62022044da25ae99ad5c6b416662dbb06f11b9ed1584285ce59d731875b626
font_01_sfnt_off0000ecab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECAB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000104c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104C2 10724 bytes
SHA-256: d285ae7e8c20295b31df261239f84d705ee76a628d2343243f48387054126053