Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac71813af1379b32…

MALICIOUS

PDF

73.0 KB Created: 2021-09-20 04:44:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: e2195568c624aef4562f5bdef7494e48 SHA-1: 38cf6b470394cb670bf5401a73ae05f5a118dc07 SHA-256: ac71813af1379b32c98a99b5866d5a7f723cbfd20eaaa6b503a04d7c000317b5
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as a malicious PDF by ML classifiers and ClamAV. It contains numerous embedded URLs, many of which point to PDF files hosted on potentially disposable domains, suggesting a link farm or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure the true malicious intent by distributing links across many low-reputation hosts. No scripts were extracted, but the overall structure and heuristic firings strongly suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9940

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://rrarental.org/upload/file/ruritanolixotogakej.pdf In PDF document text
    • http://robotsuk.com/luckingbros.co.uk/userfiles/files/zeletipoj.pdfIn PDF document text
    • http://gingerwooddesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d86958319b---pajetelaxisonusilepo.pdfIn PDF document text
    • https://0922.sproname.com/files/userfiles/files/50232806400.pdfIn PDF document text
    • http://lawyergz.net/uploadfile/files/15194573602.pdfIn PDF document text
    • http://xinghui.co/upload/ckimg/files/202109140501424992.pdfIn PDF document text
    • https://plentis.eu/ckfinder/userfiles/files/14507044584.pdfIn PDF document text
    • https://xn-----6kcabagcgfjsxjciriy6alkh6a7aqk.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/48f02b09a75afbd7900cde0f2856a35e/gorufekegan.pdfIn PDF document text
    • http://baocaosuhoatoc.com/luutru/files/87218145647.pdfIn PDF document text
    • http://jezirka-biobazeny.cz/UserFiles/File/wepor.pdfIn PDF document text
    • https://duvarkagidierzincan.com/userfiles/file/sukugejujawipede.pdfIn PDF document text
    • http://innobiztour.com/FileData/ckfinder/files/20210919_FDF748E5C0D345D9.pdfIn PDF document text
    • http://aallergy.friend-match.com/upload/files/23106358743.pdfIn PDF document text
    • http://sunil.kr/uploadfile/fckeditor/file/97979215848.pdfIn PDF document text
    • http://ahcxdq.com/uploads/file/18094912573.pdfIn PDF document text
    • http://naturalfurnish.com/userfiles/file/30315001807.pdfIn PDF document text
    • http://chanakol.com/ckfinder/userfiles/files/bidajena.pdfIn PDF document text
    • http://vigova.com/Images_upload/files/tulofanuludetaxeku.pdfIn PDF document text
    • https://megalightgroup.lv/uploads/files/39615152519.pdfIn PDF document text
    • http://wizclub.net/upload/userfiles/file/fiporopasiwezetadivival.pdfIn PDF document text
    • https://ikorti-iao.com/userfiles/files/66339523813.pdfIn PDF document text
    • http://lamorenj.com/userfiles/files/65560680163.pdfIn PDF document text
    • https://baongochoa.com/upload/file/zugamepisulivufudipapar.pdfIn PDF document text
    • http://fc-junajted.com/upload/datoteke/13691641627.pdfIn PDF document text
    • http://uforoi.com/app/webroot/uploads/files/jerupizusemapu.pdfIn PDF document text
    • http://getem.eu/files/file/56319545081.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=how+to+download+music+on+musicoletPDF 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_off0000bb6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB6A 16272 bytes
SHA-256: 541437ae8f4bd4d7ac7dc9ab4839df8fe5f76feadda43245dbaa098dabbd86b5
font_01_sfnt_off0000e574.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE574 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fd8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD8B 10608 bytes
SHA-256: 1d4eb15ec70cb60c875162b2acfa7b20dcda97f837ebf525bd8e1676b89931c2