Malicious PDF — malware analysis report

Static analysis result for SHA-256 953dccee98598e62…

MALICIOUS

PDF

85.9 KB Created: 2021-09-08 09:28:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-16
MD5: 157e22ac466fba91899899c04a6d5549 SHA-1: f9307eb6fe1fa2a6d0acd10e98694d67caa2cfe4 SHA-256: 953dccee98598e624d7979d489af360dd6c4ab6400c6686966242af1944ed6dc
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many pointing to compromised WordPress upload directories, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to redirect users to phishing sites or download further malware. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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 http://www.sbawerribee.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a1f01688f78---65703865170.pdf In PDF document text
    • http://tatishev.ru/admin/ckfinder/userfiles/files/17418877387.pdfIn PDF document text
    • http://theydeserveastamp.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a17ec9cbb4e---zilidubukasozixolade.pdfIn PDF document text
    • https://qamarapps.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d30f640a55---27292313117.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c87f9f5c2db---71836937879.pdfIn PDF document text
    • https://aadhaarretail.com/administrator/imagetemp/file/getidafekifazavo.pdfIn PDF document text
    • http://master-stroi76.ru/userfiles/file/78078228197.pdfIn PDF document text
    • http://www.barbazan-debat.fr/ckfinder/userfiles/files/49227024867.pdfIn PDF document text
    • http://schooldistrictservices.com/clients/f/f6/f6ab1571d2cdf5e569af7b76e288b17c/File/xavopokuk.pdfIn PDF document text
    • http://www.aluvascientific.com/UserFiles/file/85487092853.pdfIn PDF document text
    • http://ahdongjiu.com/upload_fck/file/2021-4-29/20210429210900459930.pdfIn PDF document text
    • https://porterbrothersltd.com/app/webroot/uploads/86777714842.pdfIn PDF document text
    • https://tkquiz.com/userfiles/file/nabekirezu.pdfIn PDF document text
    • http://winkeleninzundert.nl/uploadimages/files/genadavogovivasuxoror.pdfIn PDF document text
    • http://countrysquirefoods.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092481c58ef2---rodapijasofeviminegedat.pdfIn PDF document text
    • http://caythuocdangian.net/images/files/78691394480.pdfIn PDF document text
    • http://zoldjogsi.hu/uploads/files/wugisuxulonapedeweleja.pdfIn PDF document text
    • http://orderkai.com/uploads/files/pevil.pdfIn PDF document text
    • http://ekolojikweb.net/upld/userfiles/file/10484317048.pdfIn PDF document text
    • https://textolinguisticsolutions.com/upload/editor/file/63986416566.pdfIn PDF document text
    • http://opusincertum.it/userfiles/files/puginebunaguliva.pdfIn PDF document text
    • http://conwaychristian.org/wp-content/plugins/formcraft/file-upload/server/content/files/16077d91781937---1754373224.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16077c2fdb134b---mozoxivolatima.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=parallelogram+rectangle+rhombus+square+worksheet+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_off0000e295.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE295 11540 bytes
SHA-256: 866cd5f24559da13e4c16d6e512e072b9d3c680fef4606e8ad6934f0348102b6
font_01_sfnt_off0000fd1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD1B 19884 bytes
SHA-256: 06bb0405eb8b3a99265fa653a21f48191d3f961f8f546490fc408a1c91d2ed0f
font_02_sfnt_off0001312c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1312C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1