Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9bc9c55a146799e…

MALICIOUS

PDF

73.4 KB Created: 2021-09-01 21:21:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 98e8b7a6be258fd366642513fef86cb5 SHA-1: 5592290b9911548b293bc74c392ed3c7ee8aa59f SHA-256: a9bc9c55a146799e4742fe2b76b4b1dc8837a072a5826461298562d7b088127a
96 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by an ML classifier. It contains numerous embedded URLs, many of which point to compromised WordPress sites, suggesting a link farm or redirection scheme. The heuristic 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' specifically indicates links to compromised WordPress upload storage, reinforcing the malicious intent. No scripts were extracted, and the document body was unreadable binary data.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/e7d33bb3c89665d1878165fd14ef6794/72361870073.pdf In PDF document text
    • https://www.zaantraining.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160de14f80c87e---19155639967.pdfIn PDF document text
    • http://www.risingstars.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1608b8f1dd4774---93209849574.pdfIn PDF document text
    • http://ajivikafinance.com/userfiles/file/88083951005.pdfIn PDF document text
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f59fbdf906---polijinudonerav.pdfIn PDF document text
    • http://mcap.cz/images/uploadedimages/file/duzusol.pdfIn PDF document text
    • http://www.suffaheducation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9c2ab50506---12814679309.pdfIn PDF document text
    • https://motionslam.com/wp-content/plugins/super-forms/uploads/php/files/f067ff2b777735fac53c36752efe2226/7744987557.pdfIn PDF document text
    • https://radiosmile.hu/upload/file/6814168255.pdfIn PDF document text
    • http://powercleanperu.com/cms_powerclean_2015/sgi_userfiles/userfiles/files/65371240652.pdfIn PDF document text
    • http://koutingchina.com/upload/files/45226951988.pdfIn PDF document text
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/a87f2cdfaa5db110a304f33304898362/95906561352.pdfIn PDF document text
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c5ab92927d---fawijazenobaxidujores.pdfIn PDF document text
    • https://xehowo24h.com/images/ckeditor/files/liwijej.pdfIn PDF document text
    • https://orsam.org.tr/paketler/ckfinder/dosyalar/files/70522972944.pdfIn PDF document text
    • http://brukbet.com/user_images/file/damuxafu.pdfIn PDF document text
    • http://xn--80aaeiengkwpz6p.xn--p1ai/pub/file/89884053714.pdfIn PDF document text
    • https://rmissio.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160855bf46979e---27845483756.pdfIn PDF document text
    • https://www.heainc.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607bc71e8edec---66131743293.pdfIn PDF document text
    • http://bundoreh.com/fckeditor/files/file/kajujusegolo.pdfIn PDF document text
    • http://www.reroofingbrisbaneqld.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160d5a72ce797a---32229133892.pdfIn PDF document text
    • http://escrima-rlp.de/userfiles/file/givaberunazetuzuguja.pdfIn PDF document text
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606d353b1a3c4---67370859148.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=what+does+mk+stand+forPDF 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_off0000bda6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDA6 16384 bytes
SHA-256: 0ec7c71dbecdd0eb5d0980f54179cf3d47e774ae127cf5566ab9c83dd1d5306f
font_01_sfnt_off0000e7db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7DB 10564 bytes
SHA-256: 6304aa663ff61cb99117adb8f70c9b6be3265815d0b4b619b8cfab506e7a3e73
font_02_sfnt_off0000ffcc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFCC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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