Malicious PDF — malware analysis report

Static analysis result for SHA-256 8fcf421f564a0f45…

MALICIOUS

PDF

72.1 KB Created: 2021-09-10 21:49:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 2a1e6230eff2414b0ab3f3965fcbee04 SHA-1: 5592e201ed57cf06238542ca8ea815bce4733c2a SHA-256: 8fcf421f564a0f45457ecf05e18bd61db1b5c01ba0be0a6d32a0430d45fef5b6
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to compromised CMS uploads or disposable hosting, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, supporting the conclusion that it is used for malicious redirection, likely to phishing sites or to download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9979

Heuristics 5

  • 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://laborke.ru/uplcv?utm_term=evil+operator+app+download PDF link annotation
    • http://enidental.com/userfiles/file/20210904113009.pdfIn PDF document text
    • http://gift-founder.com/archive/upload/files/85091936578.pdfIn PDF document text
    • http://studioriboldi.eu/userfiles/files/pumudasubizetujowa.pdfIn PDF document text
    • http://timebymtm.com/upload/files/52304588102.pdfIn PDF document text
    • http://dezis.ru/uploads/files/14910566397.pdfIn PDF document text
    • https://villamishkan.com/310renonew/front/images/files/kizokakowizal.pdfIn PDF document text
    • http://federicozucchettiarchitetto.eu/userfiles/files/66120015437.pdfIn PDF document text
    • http://www.radeton-cz.vasestranky.cz/ckfinder/userfiles/files/26367461574.pdfIn PDF document text
    • http://www.aceitunasdelguadalhorce.es/ckfinder/userfiles/files/32393206989.pdfIn PDF document text
    • http://www.lifestaralberta.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613815ac83bc1---luvuniwowutoxititemim.pdfIn PDF document text
    • https://performanshost.com/calisma2/files/uploads/74646540391.pdfIn PDF document text
    • https://romalasergroup.com/userfiles/files/dazibowe.pdfIn PDF document text
    • http://uat2.hkha.com.hk/ckfinder/userfiles/files/58852207663.pdfIn PDF document text
    • http://nadafashionbelt.com/Uploads/file/40566947009.pdfIn PDF document text
    • https://www.democratum.com/wp-content/plugins/super-forms/uploads/php/files/d350caeb2c6821dbd08eaa920e4483ea/25293609471.pdfIn PDF document text
    • https://portalkucharski.pl/app/webroot/media/files/pipinawujosivezida.pdfIn PDF document text
    • http://fd-health.com/upload/ckeditor/files/boniripusufevas.pdfIn PDF document text
    • https://ostrichpharmaceuticals.com/userfiles/file/puzebilelobosirowed.pdfIn PDF document text
    • https://penzion-palice.cz/content/belidiwiwukulufof.pdfIn PDF document text
    • http://ophtalmic-overnight.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161347f8d08854---78738654032.pdfIn PDF document text
    • http://wxbeimei.cn/upload/ckimg/files/202109021806348082.pdfIn PDF document text
    • https://mk-sito.it/uploads/file/xajazenobo.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_off0000b962.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB962 10352 bytes
SHA-256: afcd89b9b8ab06fa0eea8b7d41b99e54153de77501e30d2421080744cdd6c0d3
font_01_sfnt_off0000d0de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0DE 16260 bytes
SHA-256: a6cd095b770b2bae05a64219645ca4f52cf1237807a68c64337fcc472b8f4b9d
font_02_sfnt_off0000fab7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAB7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1