Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d637b5ee631e0b…

MALICIOUS

PDF

79.7 KB Created: 2021-09-06 11:44:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 72a31968c534ed87ddd5b963a70cbd1f SHA-1: 73d547ad74a60fcf53c1cd53232217177e2f8ce8 SHA-256: 81d637b5ee631e0b6523f3ad3c144f1686291a8200cf06c9050af77a2c445e7a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to distribute malicious content or engage in phishing. Although no scripts were explicitly extracted, the PDF structure and embedded URLs strongly suggest it's part of a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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://socohoteldanang.com/uploads/image/files/89265643290.pdf In PDF document text
    • http://zatacorp.com/upload/files/69185026826.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/160b463c546145---40893209849.pdfIn PDF document text
    • https://signika.pl/Upload/file/gokepivekulowos.pdfIn PDF document text
    • https://whitelightdesign.com/wp-content/plugins/super-forms/uploads/php/files/1ac67966c536306aeb0e6200aa79abad/vajejipu.pdfIn PDF document text
    • https://www.webhisto.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160b4739ba0dbe---4766531299.pdfIn PDF document text
    • https://mmgrowersg.com/ckfinder/userfiles/files/1356332448.pdfIn PDF document text
    • http://www.hgbehringer.de/img/files/files/tunibuwisixijirisoso.pdfIn PDF document text
    • https://www.pharmaright.ca/wp-content/plugins/super-forms/uploads/php/files/0vjglvskejokbl6eeg6qg1u8lh/45557725405.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607215560935f---narovosinox.pdfIn PDF document text
    • http://csc0451.com/userfiles/file/20210807022027_iz4vgk.pdfIn PDF document text
    • https://tucsonhomewindowtint.com/wp-content/plugins/super-forms/uploads/php/files/55144ff87cb67c516ccd12c3480c5d98/94207038024.pdfIn PDF document text
    • http://eugensa.lt/app/webroot/uploads/userfiles/files/77266314211.pdfIn PDF document text
    • https://cristalensi.com/public/File/josuxamebo.pdfIn PDF document text
    • http://yejida.com/userfiles/file/97476144616.pdfIn PDF document text
    • http://cappellastudio.it/userfiles/files/38590485583.pdfIn PDF document text
    • http://worksafeorg.com/wp-content/plugins/super-forms/uploads/php/files/hg1p4afgmm1kockiua2fb9d2u0/68242977861.pdfIn PDF document text
    • https://sokolzgierz.pl/web/uploads/files/13662092621.pdfIn PDF document text
    • http://sushiosushi.com/uploads/files/jovowapugosaxobejewu.pdfIn PDF document text
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1608ee2fb198dd---jizugevevuto.pdfIn PDF document text
    • https://ceadersvalet.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c6cc4b963a---98173736792.pdfIn PDF document text
    • http://sgyscom.com/upload_fck/file/2021-7-14/20210714085242440020.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16089c4367d064---vutafafures.pdfIn PDF document text
    • http://anhuizhkj.com/upload_fck/file/2021-5-2/20210502082705193408.pdfIn PDF document text
    • https://gtnet-engine.com/ckfinder/userfiles/files/ledarogepewujosemin.pdfIn PDF document text
    • http://airmon.hu/images/files/mugaxabinonazojajatu.pdfIn PDF document text
    • http://www.veronicaneal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/16094a61d29515---46237043017.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=simple+past+worksheet+docPDF 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_off0000d215.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD215 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ea2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA2C 10928 bytes
SHA-256: 138ba7157a0b36832b07eb82d3d954815177a2160334046ea484d748f5d209fa
font_02_sfnt_off00010381.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10381 17456 bytes
SHA-256: deccb5ba736723b58b3aa87cf34cc5f260fcfbb25e8c44919530837b33fa604c

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