Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb93e31a0f2878c3…

MALICIOUS

PDF

53.8 KB Created: 2021-09-27 20:47:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: c947b2d1b9ef2671e955818f95e3177c SHA-1: 8fc28b35b1aa2173695fd244958168605e159996 SHA-256: cb93e31a0f2878c3cd79a30ce3883fc8991b51677219d1faeb0e1e4bf12feef4
154 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to redirect users to malicious sites. The presence of these links and the overall structure suggest an attempt to lure victims for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8114

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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
  • 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://chcial.ru/uplcv?utm_term=hacking+tricks+for+android+mobile PDF link annotation
    • http://av72-reklama.ru/userfiles/file/163158352540477bc2adceef4d2c90.pdfIn PDF document text
    • https://www.profiemg.cz/upload/ck/files/keviku.pdfIn PDF document text
    • http://www.catedralirodahaz.hu/data/editorfile/20553585001.pdfIn PDF document text
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/abfada6de52936a46b802cf3aa81d0d1/zarividoxexa.pdfIn PDF document text
    • https://lingchuanfloor.com/app/webroot/userfiles/files/13923556625.pdfIn PDF document text
    • https://www.hs-hofgastein.salzburg.at/ckfinder/userfiles/files/98897773416.pdfIn PDF document text
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/161325abe64ccb---nakimewewobuxuva.pdfIn PDF document text
    • http://tatvideo.ru/ckfinder/userfiles/files/pasusozavit.pdfIn PDF document text
    • https://cytokin.ca/upload/editor/file/21364882288.pdfIn PDF document text
    • http://deliver.cueicha.com/assets/upload/files/fejijasen.pdfIn PDF document text
    • http://www.tractortools.cz/ckfinder/userfiles/files/wonadodasunibume.pdfIn PDF document text
    • http://taemyung.com/data/upload/file/73527730614.pdfIn PDF document text
    • http://elitvorota.ru/f/file/5937217555.pdfIn PDF document text
    • https://magiccat.pro/ckfinder/userfiles/files/xipepurozu.pdfIn PDF document text
    • http://abwingstop.com/uploads/files/77966748544.pdfIn PDF document text
    • http://impressivetravelvietnam.com/upload/files/tekesus.pdfIn PDF document text
    • http://www.parkwaytransplant.com/media_upload/upload/files/13870344743.pdfIn PDF document text
    • http://www.dkmodels.net/ckfinder/userfiles/files/nuvujadopipazoroniloz.pdfIn PDF document text
    • https://shopexpert.com/app/webroot/files/userfiles/files/ridarug.pdfIn PDF document text
    • https://alismobile.co.uk/wp-content/plugins/super-forms/uploads/php/files/fc32abdbfe4549fbeac039ed04b2e16c/62161210771.pdfIn PDF document text
    • https://atputasbazes.lv/images/userfiles/files/46442410656.pdfIn PDF document text
    • http://digivideos.net/ckfinder/userfiles/files/64464931867.pdfIn PDF document text
    • https://www.isnb.co.uk/wp-content/plugins/super-forms/uploads/php/files/b093eca3e773bfc75f67de5d614e6128/80453064231.pdfIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b64a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB64A 11040 bytes
SHA-256: 34d7f4183742c3629558c81ea3c99515c697d9f264c37a1325d1d0f5a455ccdc