Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7990d5831d8f1b9…

MALICIOUS

PDF

91.2 KB Created: 2021-09-24 04:24:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 8fa0d5d7fd7aeace0102dce80ad22a3b SHA-1: c5652e120b4be7f5ab5dbf0892496df221609c5e SHA-256: a7990d5831d8f1b93361a7a8b18f913348fc0760390f742c7c47c02f88c1a998
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by multiple heuristics as a link farm, with many URLs pointing to potentially compromised or disposable hosting. ClamAV detected it as a phishing trojan. While no scripts were explicitly extracted, the nature of PDF link farms often involves JavaScript to facilitate redirection, hence the inclusion of T1059.007. The overall structure and URL distribution suggest a phishing or malware distribution attempt, likely delivered as an attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://transmilenio.net/datamont/userfiles/file/71086880085.pdf In PDF document text
    • https://siltri.com/fck_upload/file/tadozobav.pdfIn PDF document text
    • http://capitaloffice.pl/fotki/file/52616732567.pdfIn PDF document text
    • http://warmistore.com/userfiles/file/veruxudakixubekamu.pdfIn PDF document text
    • http://belv.ru/userfiles/file/numixifarixako.pdfIn PDF document text
    • http://ryanoomen.nl/uploadimages/files/36034204093.pdfIn PDF document text
    • http://antwerp-rentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d0b477f2d9---bezud.pdfIn PDF document text
    • http://gcsiva.com/files/userfiles/file/42996832957.pdfIn PDF document text
    • http://www.majbrno.cz/uploads/files/xukafete.pdfIn PDF document text
    • http://brixtontaxi.com/survey/userfiles/files/bomakemivake.pdfIn PDF document text
    • http://asesoriagarpe.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f09a2e8b0b---17265531075.pdfIn PDF document text
    • https://charming-dc.com/uploads/files/202109061805377371.pdfIn PDF document text
    • http://www.gobarging.com/uploads/textareas/file/lagij.pdfIn PDF document text
    • http://shiokuda1.com/contents/files/52190394715.pdfIn PDF document text
    • https://ontech.vn/images/ckeditor/files/fegojap.pdfIn PDF document text
    • https://irish-setter-zucht.info/ckfinder/userfiles/files/xixidarakadojoxip.pdfIn PDF document text
    • https://grandhotelushba.com/userfiles/file/66971243054.pdfIn PDF document text
    • https://takipcisec.com/calisma2/files/uploads/sokesijudirajivolumoxejan.pdfIn PDF document text
    • http://www.deewanalarab.com/up_imgs/40433665150.pdfIn PDF document text
    • http://romanakladatelstvi.cz/userfiles/file/27616557050.pdfIn PDF document text
    • http://alarmy-kamery24.pl/userfiles/file/visusox.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/abdfad627ffc55a87bb73ae5bafa1bfd/folalafomusifokusiveri.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=the+bachelor+2020+watch+online+freePDF 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_off000100f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100F3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011905.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11905 17296 bytes
SHA-256: 2b7982e6166cc0ad5139783155b0ec2ae1a620c3a750af3f04c6773c53764caf
font_02_sfnt_off00014666.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14666 10696 bytes
SHA-256: 15c8d139342e249796f36a8f9f8f12ed40fc45fdbca41415981a0c850dace7bf