Malicious PDF — malware analysis report

Static analysis result for SHA-256 639bd12dc0789027…

MALICIOUS

PDF

75.9 KB Created: 2021-09-18 12:02:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 21c55ca8f5f8d5266577b3c63e335dc8 SHA-1: 24c48c0d29939a43d68d5d524ddff4f82c55ce02 SHA-256: 639bd12dc0789027d0aff2ee77b42e2c2c6441f53543e950c5af64908dfe835c
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for executing malicious code. It also features a link farm pointing to various domains, some of which are hosted on compromised CMS uploads, suggesting an attempt to obscure the final destination. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://myflora888.com/ck_files/files/3677803442.pdf In PDF document text
    • https://umutisi.com/umut/upload/files/depijupeleve.pdfIn PDF document text
    • http://cutskytools.com/d/files/xivovagukikunexu.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140bb3d3e3bf---79883104010.pdfIn PDF document text
    • http://windcampus.com/wp-content/plugins/formcraft/file-upload/server/content/files/161404bd756373---mabarabirasorodewazowed.pdfIn PDF document text
    • http://keralastatetailorsassociation.com/userfiles/file/93606355744.pdfIn PDF document text
    • http://uniondeautoescuelas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d963e5aa8c---xararezilewoxan.pdfIn PDF document text
    • http://ordineveterinarireggioemilia.it/userfiles/files/gijijibalivof.pdfIn PDF document text
    • http://szyqjsj.com/UploadFile/file/20210908095447416.pdfIn PDF document text
    • http://constantemails.com/userfiles/file/1631785885lafexune.pdfIn PDF document text
    • http://hanart21.com/files/userfiles/file/71758834559.pdfIn PDF document text
    • http://logo4you.dk/userfiles/file/kokof.pdfIn PDF document text
    • http://giadinhmedia.com/uploads/files/bagaxarumixutubo.pdfIn PDF document text
    • https://jobtiara.com/files/files/91484722003.pdfIn PDF document text
    • https://oriontradecom.com/ckfinder/userfiles/files/kitizuvesikolarug.pdfIn PDF document text
    • https://isagrinio.gr/userfiles/88909965372.pdfIn PDF document text
    • https://marblobath.com/app/webroot/img/files/lipunelotumuxuzeziloti.pdfIn PDF document text
    • http://esejsc.com/upload/files/22118931756.pdfIn PDF document text
    • http://aquarium-kochi.com/app/webroot/ckfinder/userfiles/files/85965130996.pdfIn PDF document text
    • http://studioprogettoarchitettura.eu/userfiles/files/jimarogebutaxerefer.pdfIn PDF document text
    • https://hse.tw/upload/file/jamovoranavidaseba.pdfIn PDF document text
    • https://tndvn.com/js/ckfinder/userfiles/files/40730671004.pdfIn PDF document text
    • http://gunjanjain.com/app/webroot/js/uploads/files/44618800030.pdfIn PDF document text
    • https://maintogelonline2.com/contents/files/zuxiluk.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=tekken+tag+tournament+2+android+downloadPDF 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_off0000c473.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC473 10784 bytes
SHA-256: 8dd3c031a0de1084bc411e93b4a85713a35bc7988463d773f2d53e393e0b4097
font_01_sfnt_off0000dd30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD30 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f542.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF542 17008 bytes
SHA-256: 240a7022df963cac78cc25cac90c3b5df36ccc43e7d0955f54a61ace954f3f98

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