Malicious PDF — malware analysis report

Static analysis result for SHA-256 61ff559401ffd08a…

MALICIOUS

PDF

83.1 KB Created: 2021-09-04 09:31:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 75907551c85a68435471c978baa9d6a3 SHA-1: f4577af8bd38d8309fadd9da36e5ed388e58bbec SHA-256: 61ff559401ffd08a0826815e76c83a3a9367e51846780f1e58d4c040fc8ee88a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The PDF contains numerous links to external websites, many of which are hosted on compromised CMS uploads or disposable hosting, suggesting a link farm or phishing lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this. While no scripts were explicitly extracted, the PDF structure and link farm behavior are consistent with techniques used to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://www.jahnigterbraak.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607c02acde7e7---xilixojapu.pdf In PDF document text
    • https://semsaesp.com/ckfinder/userfiles/files/rited.pdfIn PDF document text
    • https://www.ogblfrontaliers.fr/wp-content/plugins/super-forms/uploads/php/files/5f1p7t4bmbs10h7bsg89ag2gq5/24034432174.pdfIn PDF document text
    • http://www.gunyagder.org.tr/wp-content/plugins/super-forms/uploads/php/files/2usspglk36qn1vqo41bsna2kh2/fitatigadowakatuba.pdfIn PDF document text
    • https://iasvn.org/Images_upload/files/loxiruw.pdfIn PDF document text
    • https://poulinstrapscan.com/userfiles/file/sobunopamufo.pdfIn PDF document text
    • http://pi-consulting.ch/download/62804098023.pdfIn PDF document text
    • https://www.apartamentselsllacs.com/wp-content/plugins/super-forms/uploads/php/files/9eea6tdg3n4v6v0ia1a108o6aq/famakexitod.pdfIn PDF document text
    • https://www.limratechnologies.net/wp-content/plugins/formcraft/file-upload/server/content/files/160d0b07df3290---jawilu.pdfIn PDF document text
    • https://anne-berger.de/sites/anne-berger.de/files/fkcfile/sosojo.pdfIn PDF document text
    • http://www.klpreschool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606eaa5015965---41295821131.pdfIn PDF document text
    • http://djpress.pl/Image/files/9535017237.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ac5892e663c---22776160168.pdfIn PDF document text
    • http://www.everhouse.lt/wp-content/plugins/formcraft/file-upload/server/content/files/1608ce5eb2f8a1---18324038111.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/1607009c62144e---fejubutifaguziposikili.pdfIn PDF document text
    • http://culbertsonlawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/43613879206.pdfIn PDF document text
    • https://joinvita.com/neu/userfiles/file/tadupaxavokuzipesigufeg.pdfIn PDF document text
    • http://botanicgardenscafe.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160967fb94c4b3---60566648881.pdfIn PDF document text
    • http://a-aqua.fr/ressource/site-image/files/kumavujavemoriwodozinin.pdfIn PDF document text
    • https://la-klamm.org/userfiles/file/9356920591.pdfIn PDF document text
    • http://abcbyspu.net/ckfinder/images_store/files/jotiw.pdfIn PDF document text
    • https://kodeac.com/wp-content/plugins/super-forms/uploads/php/files/nmposri5iukchtdfjuphbemarl/dubavujasude.pdfIn PDF document text
    • http://baloneacessorios.com/_upload/file///50229786741.pdfIn PDF document text
    • https://innotek.vn/uploads/news_file/filizevadunogoreguju.pdfIn PDF document text
    • http://toflight.mobi/attachment/ckeditor/files/50d3410d7fb1f732243a97c68cb4d719.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=american+academy+of+otolaryngology+guidelines+pdfPDF 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_off0000dda6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDA6 11160 bytes
SHA-256: c177a2767a62f222fdc9081350d33e4a383e986c8308763c2359946bced2ec2c
font_01_sfnt_off0000f78d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF78D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010f9f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F9F 18020 bytes
SHA-256: 10333a82909c67f0588e31e86322331b8279692369d820ba29d7f630c81042de