Malicious PDF — malware analysis report

Static analysis result for SHA-256 4877d578a0d28b05…

MALICIOUS

PDF

71.2 KB Created: 2021-06-15 16:41:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 3ed245419f89ce5e079a131fd3c7328c SHA-1: 68e8b1f5a74caf4fb126f09b684a8459af05761c SHA-256: 4877d578a0d28b05bdf1914f54c5e9be1c8e8dbb86327d6f57ebc104d05a9205
156 Risk Score

Malware Insights

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

The PDF contains multiple links pointing to compromised WordPress sites and other domains, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body, though heavily obfuscated, appears to be a worksheet title, likely a lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://wastran.ru/uplcv?utm_term=classification+of+elements+worksheet
    • https://wscnaturalhealings.com/wp-content/plugins/super-forms/uploads/php/files/0efd2b8acd85aeb7f5d23e0d8fbfa39e/widuru.pdf
    • http://antifftech.com/uploadfile/file/%5C/2021050912434899.pdf
    • http://blessedfamilycovenant.org/clients/c/cb/cb727bc273eb4203dc66fb73741ae5ae/File/68099920183.pdf
    • http://ip-golubev.ru/ckfinder/userfiles/files/37074631999.pdf
    • http://provia-events.de/pics/fotos/1/file/55908520887.pdf
    • https://luxartparquet.com/wp-content/plugins/super-forms/uploads/php/files/f13fa58813bcb548c42b1707c033cf39/19411053596.pdf
    • https://abril.pe/wp-content/plugins/super-forms/uploads/php/files/na1ia87jekudp1fn5tlio7crrf/2701440002.pdf
    • https://www.geosuiteonline.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b3154c112e2---kamasovewizuvuxanawedo.pdf
    • https://binarbaidfabrication.com/public_html/userfiles/file/rufur.pdf
    • http://tamker.hu/userfiles/file/33571343653.pdf
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094639a54a2f---29240873131.pdf
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/1bd4368540fd0a57d896a2bc10f4414f/wefigubepavoze.pdf
    • http://www.movingintofreedom.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083f9d82b634---80101213641.pdf
    • https://csom.cz/wp-content/plugins/super-forms/uploads/php/files/9d6fcf014650cb392a07b89933899b1c/zawotupidetenimebugekole.pdf
    • http://botosani.ro/img/uploads/file/tezitogapotar.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f8a53d8914---xevetufaje.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000da1a.bin
9977099d100cfa732fbbf94023163124e104163a700dc593dbb0e3b0811dc678		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDA1A 5180 bytes
font_01_sfnt_off0000eb9e.bin
37a54afaa89c06ea443a8ddd568d2c9c47e4a256ec9430816f2622e184df97cf		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEB9E 10932 bytes

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