Malicious PDF — malware analysis report

Static analysis result for SHA-256 8de9fbcc1f1dc08e…

MALICIOUS

PDF

88.1 KB Created: 2021-09-17 23:34:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 93614b66661dca52f07aa5d59e7c07cb SHA-1: de15c447664e020b319c175fe957c23eb1855eb0 SHA-256: 8de9fbcc1f1dc08eb2c29ed2a5ebc6df5ab35028ddeafc3a783ecf3420e91d23
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by a ML classifier and ClamAV, indicating a phishing or trojan threat. It contains numerous embedded URLs, many of which point to compromised CMS upload directories or are part of a link farm hosted on disposable domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather for search engine optimization or to obscure malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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://cakesandcupcakes.net/userfiles/files/45436417909.pdf In PDF document text
    • https://agribusiness.pk/wp-content/plugins/formcraft/file-upload/server/content/files/1613e3d232bfd5---8841850929.pdfIn PDF document text
    • http://chinhlytailieuluutru.com/media/ftp/file/pevuduzebukopeg.pdfIn PDF document text
    • https://ceylanotel.com/firma/files/fomukezu.pdfIn PDF document text
    • http://wine-paraphernalia.com/files/winep/_repo/file/77332472364.pdfIn PDF document text
    • http://hnsunnyfood.com/d/files/93275151739.pdfIn PDF document text
    • http://sccsfz.org/upload/2021-09/sosube.pdfIn PDF document text
    • https://kildevangen.dk/files/bivovowowolivexagijaxib.pdfIn PDF document text
    • https://coverline.ro/userfiles/file/12151780342.pdfIn PDF document text
    • https://karpzbeldowa.pl/uploads/userfiles/files/91371467325.pdfIn PDF document text
    • http://dichvugiayphep.net/hinhanh_fckeditor/file/19482282831.pdfIn PDF document text
    • http://alternativefitness.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161354e6c3f4de---larol.pdfIn PDF document text
    • https://www.andimoda.com/wp-content/plugins/super-forms/uploads/php/files/a237ce9a812e6e853520c4bc7f85d545/68736969667.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-9-17/20210917003218108597.pdfIn PDF document text
    • https://pushtypathshala.com/demo/aims/files/images/files/pemopamorimurorisuladu.pdfIn PDF document text
    • http://philipwillettelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/38365783492.pdfIn PDF document text
    • https://aadharshilaschool.org/userfiles/file/79799005222.pdfIn PDF document text
    • http://aiswaryamatrimonials.com/fck_uploads/file/86079366282.pdfIn PDF document text
    • http://ilsungwarehouse.com/userData/ebizro_board/file/23145921574.pdfIn PDF document text
    • http://greenhere.cn/upload/ckimg/files/202109132055328567.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=what+is+pierre+cardin+most+famous+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_off0000ef1d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF1D 10932 bytes
SHA-256: 2404d6ade54d8e99914bb1e89bc3eef7fa0783456e56e1cc498d7d3e94bf5d91
font_01_sfnt_off00010851.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10851 19320 bytes
SHA-256: 6f6b711f609b0dcac04e21a021a552da4b96bbcedae456adf97b25202f9c082b
font_02_sfnt_off00013aac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13AAC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1