Malicious PDF — malware analysis report

Static analysis result for SHA-256 81169c57f213f399…

MALICIOUS

PDF

80.0 KB Created: 2021-08-10 13:37:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: bb4d4ee7dab21b6e397940e01034cfe0 SHA-1: e9842525b40b161432dd4e6452f31791579a482a SHA-256: 81169c57f213f399c06c34d9de9d5ac7173cad46232eb6882b1c9caf8de259b6
96 Risk Score

Malware Insights

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

The PDF file contains a link farm, with numerous embedded URLs pointing to compromised WordPress sites and other disposable hosting. The ML classifier strongly indicated maliciousness, and the heuristics confirm the presence of a link farm designed to redirect users. The primary purpose appears to be directing traffic to potentially malicious or SEO-manipulated content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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://thaoduocquyhiem.com/userfiles/image/file/dixusapipazepa.pdf In PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16078a3df22067---64406454240.pdfIn PDF document text
    • https://ikansambel.com/contents//files/dogifakujaref.pdfIn PDF document text
    • https://digireg.pl/upload/37924894259.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d81eb3cabd9---46419000787.pdfIn PDF document text
    • https://afd.me.uk/wp-content/plugins/super-forms/uploads/php/files/70dav53pao944afoc23mj8qfid/57840913549.pdfIn PDF document text
    • https://liniagdanskzydowo.pl/files/rixavojigawopozenagobe.pdfIn PDF document text
    • http://kondicionery-domodedovo.ru/upload_picture/file/bojazofumi.pdfIn PDF document text
    • http://etkindenetim.com/resimler/files/97410300747.pdfIn PDF document text
    • https://ruxthai.com/ckfinder/userfiles/files/45361390665.pdfIn PDF document text
    • https://www.kiteschule-eckernfoerde.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ada7f52ad64---13436908186.pdfIn PDF document text
    • https://antoinepanau.com/wp-content/plugins/super-forms/uploads/php/files/f90c7a7d28161458bceefe59a7d18a92/90480240034.pdfIn PDF document text
    • https://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/26a984881132694151330493fa448027/zuxolegexusagavujuzifu.pdfIn PDF document text
    • http://veronikavilla.hu/userfiles/file/rukirafipeto.pdfIn PDF document text
    • https://grahampropertytax.com/wp-content/plugins/super-forms/uploads/php/files/982063d9d168b528ef7ca0c0795683ae/70827399772.pdfIn PDF document text
    • https://alyosserspneed.com/userfiles/files/sebit.pdfIn PDF document text
    • http://cmtsport.com/pliki/musadodugexiz.pdfIn PDF document text
    • http://studiorestagno.eu/userfiles/files/wugatutuz.pdfIn PDF document text
    • http://princeworldwide.com/multimedia/userfiles/file/88406025969.pdfIn PDF document text
    • https://bf-pomosch.ru/wp-content/plugins/super-forms/uploads/php/files/bj652dl93r6gt15dfjc7mstr22/24764879742.pdfIn PDF document text
    • http://digimaap.com/wp-content/plugins/super-forms/uploads/php/files/kkfgdc4o8b39330u8au56p2nsu/fisobemavarawugub.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=pc+matthews+vector+calculus+pdf+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_off0000d3c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3C1 11048 bytes
SHA-256: 3b85615a32cff8c549e37cbb0219d075651f0a642927e42a4cb176c529160db5
font_01_sfnt_off0000ed62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED62 17320 bytes
SHA-256: 735556a663c69db2e255f363db477845093ad4e82e70d133d2d822b91584fe32
font_02_sfnt_off00011aaa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AAA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1