Malicious PDF — malware analysis report

Static analysis result for SHA-256 73ff820189fc4da4…

MALICIOUS

PDF

83.5 KB Created: 2021-09-03 17:13:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 10e334ff913af8eb253793320e6fe0ee SHA-1: 775b6ca61651c53cddb96beff617263726d47f65 SHA-256: 73ff820189fc4da4041fa48492316a428a67b372fbfd7c5c2474550444b7e010
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. Heuristics indicate the document functions as a link farm, directing users to numerous external URLs, many hosted on compromised websites. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM firings suggests a deliberate effort to obscure the true destination and leverage potentially compromised infrastructure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://infrive.ru/uplcv?utm_term=countries+and+their+capitals+in+alphabetical+order+pdf PDF link annotation
    • http://debandhelder.nl/ckfinder/userfiles/files/21222478819.pdfIn PDF document text
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/0181a43480f3296d54126237bf9a5c3a/28776089186.pdfIn PDF document text
    • http://www.kymenhome-etsinta.net/tiedostot/files/vominapafe.pdfIn PDF document text
    • http://twfbs.com/ckfinder/userfiles/files/gopivamugezopawuji.pdfIn PDF document text
    • http://rts-3.ru/upload/files/nuwujoforovuzebi.pdfIn PDF document text
    • https://appvid.eus/userfiles/files/sowuvapujum.pdfIn PDF document text
    • http://levakov132.ru/userfiles/file/xoguxuborubifimukozitam.pdfIn PDF document text
    • https://coloreverything.love/wp-content/plugins/super-forms/uploads/php/files/d8aa601ce683714360f76acfba25f6f7/66429534085.pdfIn PDF document text
    • http://career-id.org/ckfinder/userfiles/files/dikaj.pdfIn PDF document text
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610053baf015a---fowogidogifurozivoremo.pdfIn PDF document text
    • https://viettincapital.vn/upload/files/33075512161.pdfIn PDF document text
    • http://myucmas.com/userfiles/file/vinefetajifuvaxuduz.pdfIn PDF document text
    • http://wadirumshootingstars.com/userfiles/file///bijeguwu.pdfIn PDF document text
    • http://spalovnachemolak.sk/userfiles/file/41561491418.pdfIn PDF document text
    • https://izharfoster.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c5f54d3d4ca---58985104903.pdfIn PDF document text
    • http://absolutelyneon.com/userfiles/file/83173933572.pdfIn PDF document text
    • http://makingtheturngolf.com/clients/9/92/925d9bae4ecf380f28dbe0e1390c16eb/File/melujajifupibivo.pdfIn PDF document text
    • http://scottsdalehighbeavers1978.com/clients/80197/File/timudi.pdfIn PDF document text
    • http://adria-ex.com/images/blog//file/6444067291.pdfIn PDF document text
    • http://njf724.com/basefile/janatalnajafcom/files/8468121164.pdfIn PDF document text
    • https://dbjadow.pl/attachments/file/xaxetudobomevip.pdfIn PDF document text
    • http://alexhoffordphotography.com/temp/files/file/76709127046.pdfIn PDF document text
    • http://www.netcorp.hu/data/editorfile/najosebifu.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16072f321ba563---78245406094.pdfIn PDF document text
    • 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_off0000df2d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF2D 18444 bytes
SHA-256: af6237988d954e54f96b44a32ddf8b3d71e03d65f24c873073fea45fd259eecd
font_01_sfnt_off00010ef9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EF9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012710.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12710 10988 bytes
SHA-256: c90d1975246c11a9ba09d230d3b461457fca9eda60f3b130793e4075bb3b0501

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