Malicious PDF — malware analysis report

Static analysis result for SHA-256 346ec860ca578919…

MALICIOUS

PDF

76.0 KB Created: 2021-10-13 23:58:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 391d4b743a7eeae637deb112d5d07975 SHA-1: c52a6905060c2be10843ce14769110cbd712e44f SHA-256: 346ec860ca578919e36cba8a2f73f8c7c14904a2f3f8bb21dd71f2c6245aa7f5
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to other PDF files hosted on potentially compromised or disposable domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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.globalnautique.nl/upload/files/zigerezotaserefo.pdf In PDF document text
    • https://unique-u.biz/images/uploads/file/zodisavixe.pdfIn PDF document text
    • https://rosettes.it/userfiles/file/49060765116.pdfIn PDF document text
    • http://betheaskssd.com/flash/betheaskssd.com/file/38122168237.pdfIn PDF document text
    • https://springkasteelhuren.be/userfiles/file/31866098089.pdfIn PDF document text
    • https://abyway.lv/images/ck_images/files/47173056563.pdfIn PDF document text
    • http://truhlarstvi-strakonice.cz/files/file/84962555205.pdfIn PDF document text
    • https://gospel-streams.com/asset/ckfinder/userfiles/files/dexebisofozadusalisedax.pdfIn PDF document text
    • https://multimetrics.com/ckfinder/userfiles/files/38219053173.pdfIn PDF document text
    • https://bellcera.60km.com/upload/files/kixapenuvitovedu.pdfIn PDF document text
    • http://king-tableware.com/uploads/files/202109231525032652.pdfIn PDF document text
    • http://atlantichomeportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/16156f5325b43e---vebib.pdfIn PDF document text
    • http://9jamail.com/FCKeditor/editor/filemanager/connectors/userfiles/file/66872572015.pdfIn PDF document text
    • http://cascinamana.it/userfiles/file/3103191555.pdfIn PDF document text
    • http://balone.net/_upload/file///5840329753.pdfIn PDF document text
    • https://beeshark.ro/app/webroot/files/userfiles/files/34429248078.pdfIn PDF document text
    • http://yingtailong.com/upload/file/210928092220632386ljskiuxh9g6k.pdfIn PDF document text
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615ab15477a08---20266214422.pdfIn PDF document text
    • https://www.wroclawmodelshow.pl/ckfinder/userfiles/files/gopukikewezewimaju.pdfIn PDF document text
    • https://qualityroofinnandsuites.com/nbloom/fckuploads/file/suzumexijujix.pdfIn PDF document text
    • http://witnesstherealist.com/wp-content/plugins/super-forms/uploads/php/files/effb2bda939dedbe5b4fe9429864b3b3/49364755129.pdfIn PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1615b001ce9a62---27429389889.pdfIn PDF document text
    • http://paintingservicesonline.ca/wp-content/plugins/formcraft/file-upload/server/content/files/161582fa08baf1---majazokomise.pdfIn PDF document text
    • https://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/161604d7320f2d---wugarekoxekogatujabuza.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Gsjc/~3/u-9XGpgKpwY/uplcv?utm_term=a+background+to+the+study+of+english+literature+book+pdf+downloadPDF 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_off0000c049.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC049 18056 bytes
SHA-256: ede78aac97467270f71d18f4e255d3b97052f135d675dd98a77111c18be888e6
font_01_sfnt_off0000ef5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF5D 11412 bytes
SHA-256: 6029dd042d52bc228e8dd279b0bfc0a37c036975a053631a88c5cf32cf02552c
font_02_sfnt_off000109fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109FB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1