Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1f21a915ffeace8…

MALICIOUS

PDF

70.8 KB Created: 2021-09-05 08:56:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: c59169238ff326a54b9c3ca46dc3a6a4 SHA-1: c9c969ad139ad08e9656b52bf0728b4ff164caad SHA-256: b1f21a915ffeace8af33a5be6b3c707b690b00a6d35bd0daf9c1f42cff096e1d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a link farm with numerous URLs, several of which point to compromised WordPress upload storage. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and does not provide clear instructions, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://iaestedresden.de/userfiles/file/zojotulapunadisaruten.pdf In PDF document text
    • https://cytokin.ca/upload/editor/file/nazopiboxipapoposibobu.pdfIn PDF document text
    • https://www.anandtirth.com/wp-content/plugins/super-forms/uploads/php/files/m6drf95ag1o4h0p91s8kn62bh7/zinosuzuzeferunine.pdfIn PDF document text
    • https://planningpvedh.nl/ckfinder/userfiles/files/87797849160.pdfIn PDF document text
    • https://am-system.eu/ckfinder/userfiles/files/29729006847.pdfIn PDF document text
    • https://keongracun.org/contents/files/56563024822.pdfIn PDF document text
    • https://egokituz.org/files/galeria/files/35386134991.pdfIn PDF document text
    • http://inistor.com/ufiles/files/17150965984.pdfIn PDF document text
    • https://uleiuri.ro/userfiles/file/lolupovol.pdfIn PDF document text
    • https://alixdemassy.fr/userfiles/file/94962665954.pdfIn PDF document text
    • https://amalighting.com/wp-content/plugins/super-forms/uploads/php/files/9c37c2c3d6048df8b7e125166e13e2b0/bonivifowevukoju.pdfIn PDF document text
    • https://pezenasenchantee.fr/userfiles/file/xiwadavu.pdfIn PDF document text
    • http://backupcenters.com/userfiles/file/wupapezutitobisebumagomi.pdfIn PDF document text
    • https://hardlineconstruct.ro/app/webroot/files/userfiles/files/65487996117.pdfIn PDF document text
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a256e4bfd4---lofakidafirutob.pdfIn PDF document text
    • http://livingkaneohe.com/userimages/4346658589.pdfIn PDF document text
    • http://koopmankennedyfeller.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/fikonokufezolugibix.pdfIn PDF document text
    • https://mziagroup.com/wp-content/plugins/super-forms/uploads/php/files/49aq0tgc07qh9heu92052qp34c/jipef.pdfIn PDF document text
    • http://haustechnik-hagenauer.at/fagoxarer.pdfIn PDF document text
    • https://lightingsystemscol.com/wp-content/plugins/super-forms/uploads/php/files/961a0946effb9b612d4302d5417cd748/xonofibotawivoxijufija.pdfIn PDF document text
    • https://etravelbox.com/scgtest/team-explore/uploads/files/vojisozuza.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=durianrider+lean+body+bible+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_off0000b214.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB214 16568 bytes
SHA-256: 82027b97f8e5fec9b2b431aeae4e11804d0107230e72809e5425738e8fb04ba0
font_01_sfnt_off0000dcff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCFF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f516.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF516 10664 bytes
SHA-256: ad5ca89b0f98fa7821ed177442c64e7306472005c9699cb426db73c393b7303a