Malicious PDF — malware analysis report

Static analysis result for SHA-256 31a91a5881c78b7b…

MALICIOUS

PDF

79.8 KB Created: 2021-09-20 07:48:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 73fcc27f50615d81c3275159ca070e1c SHA-1: f436240cff2382a316a84a93ed4d41f62ad985ed SHA-256: 31a91a5881c78b7b372d920648894d9c6005ed9cd6204be41358310b7228cc9a
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to multiple compromised websites, suggesting an attempt to trick users into downloading files. The ML classifier and ClamAV detection strongly indicate malicious intent. The presence of numerous external URIs and a link farm heuristic further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://seattleteriyaki3.com/uploads/files/riremaxolusi.pdf In PDF document text
    • http://wojno-stal.pl/pliki/file/tumomusafafanemo.pdfIn PDF document text
    • https://www.chablis-gautherin.com/ckfinder/userfiles/files/15479466270.pdfIn PDF document text
    • http://seibyou-koujien.com/files/files/kusipaxudazetovifawa.pdfIn PDF document text
    • http://pizzeriadevita.it/userfiles/files/15099148836.pdfIn PDF document text
    • http://lsphc.com/userfiles/file///foroludimujudobi.pdfIn PDF document text
    • http://lalitas-thaimassage-spa.de/wp-content/plugins/formcraft/file-upload/server/content/files/161473253be32d---jeluxi.pdfIn PDF document text
    • https://delaneyllc.cfonewsletter.com/ckfinder/userfiles/files/pufigi.pdfIn PDF document text
    • https://eric-parnes.com/ckfinder/userfiles/files/75015776971.pdfIn PDF document text
    • http://strandedtattoo.net/file/zulometidazad.pdfIn PDF document text
    • http://bellina.pl/userfiles/file/53574728928.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1614026e06e250---42580415961.pdfIn PDF document text
    • http://harchovyk.com/userfiles/file/wiwinoxosijen.pdfIn PDF document text
    • http://greenbrier101.com/userimages/86437132944.pdfIn PDF document text
    • http://www.laterveer-biesenbeek.nl/ckfinder/userfiles/files/4012027811.pdfIn PDF document text
    • http://acetuitioncentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16143d72545d0c---kovenitadanebuv.pdfIn PDF document text
    • http://pferdefreunde-brueckenhof.de/sites/default/files/userfiles/file/solud.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/11072949157.pdfIn PDF document text
    • http://cancercareresearch.com/userfiles/file/deneganokururojofirakux.pdfIn PDF document text
    • http://poetische-malerei.de/web/editor/files/40756442225.pdfIn PDF document text
    • http://king-tableware.com/uploads/files/202109180021362376.pdfIn PDF document text
    • http://www.tamtrebinhminh.com/public/files/22351808938.pdfIn PDF document text
    • http://yatros.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161368757989d7---nogizubibimufebetomib.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=download+apk+fall+guys+ultimate+knockoutPDF 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_off0000cea1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEA1 18500 bytes
SHA-256: efaca8ac0aa909d3bb99a295a2104e334f5f6fac4722930bae8c9d73b3a4e4e6
font_01_sfnt_off0000fed1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFED1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000116e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116E8 11256 bytes
SHA-256: f533e2280c2d6d32f6c36998df5266b07141c4e7bf80036aaf9587ff01256cbb