Malicious PDF — malware analysis report

Static analysis result for SHA-256 87b5d80464fe77e6…

MALICIOUS

PDF

75.1 KB Created: 2021-09-18 18:20:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 9115e5073c36e28900446f14aace7109 SHA-1: d231de018a2113a9f2b4d0d831c057896952ee3a SHA-256: 87b5d80464fe77e6d156d7733c3ca9f55d5cab20115aa13e4ec56e99d7d32c3e
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by an ML classifier with high confidence. It contains a link farm with numerous URLs pointing to other PDF files, many hosted on compromised CMS uploads. This suggests a tactic to distribute further malicious content or phish users. No scripts were extracted, but the presence of embedded URLs and the link farm heuristic strongly indicate a malicious intent to redirect users to external, potentially harmful, resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://crewmak.ru/uplcv?utm_term=ml+hack+skin+2020+apk+download PDF link annotation
    • http://highdesertrent.com/newsite/images/uploads/file/rejewogedogerogixubug.pdfIn PDF document text
    • http://eclickapps.in/userfiles/files/33512109217.pdfIn PDF document text
    • http://www.jobibon.com/admin/userfiles/file/55677153104.pdfIn PDF document text
    • http://3gr-group-com.gbintl.com/ci/userfiles/files/69186690019.pdfIn PDF document text
    • https://jmcoverseaspvtltd.com/uploads/files/16286103172.pdfIn PDF document text
    • http://horizonpestservices.com/userfile/21356275195.pdfIn PDF document text
    • https://tecnicadovolante.com/images/file/26154850286.pdfIn PDF document text
    • http://xn--80aguejfegacgj0ad.xn--p1ai/pict/file/nutij.pdfIn PDF document text
    • http://bangiyaparishadtoronto.ca/bpt/editor/uploadfiles/60820099244.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/161429acd1aa4d---rarek.pdfIn PDF document text
    • http://vrzion.com/data/userfiles/files/mefelalan.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f90b39569f---gufopupimezade.pdfIn PDF document text
    • http://ekorob.pl/userfiles/file/rebibivutu.pdfIn PDF document text
    • https://e-ceramika.pl/userfiles/file/75596978718.pdfIn PDF document text
    • http://tverzhilservis.ru/foktver.ru/ckfinder/userfiles/files/vibedibizositen.pdfIn PDF document text
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/16135a5ccbb58d---kimemolaj.pdfIn PDF document text
    • http://www.rolstoellift.com/wp-content/plugins/formcraft/file-upload/server/content/files/161408a959efaa---40989071887.pdfIn PDF document text
    • http://zopos.zohukum.com/ckfinder/userfiles/files/suwojipedisufumujejisu.pdfIn PDF document text
    • http://historia-bfured.hu/userfiles/file/94289408556.pdfIn PDF document text
    • http://omniatel.it/wp-content/plugins/formcraft/file-upload/server/content/files/16137a14e617a5---41571030321.pdfIn PDF document text
    • https://mygenius.ru/admin/ckfinder/userfiles/files/58722898912.pdfIn PDF document text
    • https://ntct-dz.com/ckfinder/userfiles/files/88496514596.pdfIn PDF document text
    • https://firstview.christoff-design.com/files/lerebofaxowuxuvodiw.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_off0000c172.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC172 10692 bytes
SHA-256: 2ea4638ae0410cce07f4bc8eb56f3a176c781cc354d555b8911a39f4a122e33d
font_01_sfnt_off0000d9ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9FF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f211.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF211 16728 bytes
SHA-256: 83f855fbf67407a94d13ab767a8824a98833f8430e354c4e2c6f117fc5abbb6b