Malicious PDF — malware analysis report

Static analysis result for SHA-256 81efa6b3e5d94328…

MALICIOUS

PDF

79.6 KB Created: 2021-09-05 10:49:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: cee91dcff269f9b3df348f91978115a4 SHA-1: 72bdf6ce95ef22515bc095d10e998dfc2ec11fa2 SHA-256: 81efa6b3e5d94328a8f08eb73787046a995d9bc2885a325798578979cbad495f
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it functions as a link farm. The PDF contains numerous external URIs pointing to various domains, some of which are associated with compromised CMS uploads or disposable hosting, suggesting a phishing or malware distribution scheme. No scripts were extracted, and the document body was truncated and unreadable.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://ketchas.ru/uplcv?utm_term=environmental+issues+worksheet PDF link annotation
    • https://marosme.ro/hirek/file/18005826635.pdfIn PDF document text
    • http://zerosquareonline.com/file/wejozakovebob.pdfIn PDF document text
    • http://shop-exclusive.cz/userfiles/file/74864441002.pdfIn PDF document text
    • http://cesnek-vysocina.cz/UserFiles/File/vevovepapofegu.pdfIn PDF document text
    • https://www.3dreamchurch.com/wp-content/plugins/super-forms/uploads/php/files/d2bf620c2671e6398c264f0aaa9f4060/wotudol.pdfIn PDF document text
    • http://ap116.ru/userfiles/file/81842334264.pdfIn PDF document text
    • http://lamexmarket.com/uploads/files/34030410380.pdfIn PDF document text
    • http://falerisztika.hu/tmp/rusadikebupotomuku.pdfIn PDF document text
    • http://domkomplekt34.ru/attachments/file/wajafobetetozopinew.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608871fa90301---nejafufapuj.pdfIn PDF document text
    • http://hillsdalehorseboarding.com/ckfinder/userfiles/files/jekejawuzi.pdfIn PDF document text
    • http://statsale.com/data/upload/ck/files/7710376667.pdfIn PDF document text
    • http://bezpieczna-strefa.pl/wp-content/plugins/super-forms/uploads/php/files/de4fd01bfdb915d27e1da5f001e15515/munivalebofojijor.pdfIn PDF document text
    • http://www.gieskestukadoors.nl/ckfinder/files/files/78529917733.pdfIn PDF document text
    • https://xn--80aaa1anac6cg.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/b78a434b4e2b6c8416659e77e26876a7/soduru.pdfIn PDF document text
    • http://abwninemile.com/uploads/files/jasixejumununed.pdfIn PDF document text
    • http://kielcenoca.pl/files/file/2493348874.pdfIn PDF document text
    • http://westernmaki.com/uploads/files/44708661018.pdfIn PDF document text
    • https://lufty.cz/UserFiles/files/17776043032.pdfIn PDF document text
    • https://ofertaromania.ro/ckfinder/userfiles/files/62545596909.pdfIn PDF document text
    • http://www.teeintact.com/admin/fckeditor/editor/filemanager/connectors/php/img/file/mopevinovada.pdfIn PDF document text
    • https://www.limratechnologies.net/wp-content/plugins/formcraft/file-upload/server/content/files/160aa1fec53507---dilisavalunuvujanapadura.pdfIn PDF document text
    • https://asthasupermarket.com/userfiles/file/97208683066.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_off0000d271.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD271 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ea83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA83 17968 bytes
SHA-256: fcda32149f619cd711e592d52c1891614f2da61314a4581edbe22d8a54f24f80
font_02_sfnt_off0001182a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1182A 10700 bytes
SHA-256: 845d293b45e687cbf50979db955aa84a210d90bbc3040d13a6f839d50f5d0ffd