Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f677c7a2cbad1f…

MALICIOUS

PDF

85.0 KB Created: 2021-09-14 15:36:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: e0863450c912aab305868b13e5b621af SHA-1: b55bad5b11ab890b8235a430d5acbcd79d334482 SHA-256: 81f677c7a2cbad1fd9da9ae8a2deecf5c0752788b3150ad57380542312aee07e
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm on disposable hosting. The presence of numerous external URIs suggests an attempt to redirect users to potentially malicious websites. While no scripts were explicitly extracted, the PDF structure and embedded URIs point towards a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9860

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://synerhu.ru/uplcv?utm_term=moto+g5s+plus+software+update PDF link annotation
    • https://acrgruppe.de/userfiles/file/dosorokibawevudovok.pdfIn PDF document text
    • http://tv-sat.cz/userfiles/file/bakefofebawibosogu.pdfIn PDF document text
    • https://cosmeticdermatologymiamibeach.com/uploads/data/files/75471676984.pdfIn PDF document text
    • http://patp1ryb.ru/media/file/bomepaxomeka.pdfIn PDF document text
    • https://12waktu.com/contents/files/sukenuxuledurux.pdfIn PDF document text
    • http://rtm-plus.com/ckfinder/userfiles/files/73561706567.pdfIn PDF document text
    • http://kondicionery-dzerzhinskij.ru/upload_picture/file/19815834129.pdfIn PDF document text
    • https://ddriu.hu/wp-content/plugins/super-forms/uploads/php/files/0b9becfb148d15f51ba63cca028c1821/zarabetazovas.pdfIn PDF document text
    • http://akiisushi.com/uploads/files/31183724881.pdfIn PDF document text
    • https://inprovituruguay.com/ckfinder/userfiles/files/totogapiwiboxijaza.pdfIn PDF document text
    • https://bomnuocebara.com/quangbasanpham/app/webroot/upload/image/files/watajusuniguwala.pdfIn PDF document text
    • http://musik-fachberatung-neumarkt.de/images/uploadedimages/file/98036593054.pdfIn PDF document text
    • https://vakukh.ru/wp-content/plugins/super-forms/uploads/php/files/d312a06026fd94eb8e3d8c2a35e65abe/44717774732.pdfIn PDF document text
    • http://mopi.eu/ckfinder/userfiles/files/memivovelo.pdfIn PDF document text
    • http://traiteurluc.com/userfiles/file/gefojofamamelo.pdfIn PDF document text
    • http://ambvet-trefontane.eu/userfiles/files/jutiwu.pdfIn PDF document text
    • http://adbuilder.at/ckfinder/userfiles/files/18676454223.pdfIn PDF document text
    • http://fxmeat.com/upload/file/7f1b5824479dfc4028466cec67be7a31.pdfIn PDF document text
    • http://seibyou-koujien.com/files/files/93254802251.pdfIn PDF document text
    • http://dok-vo.ru/userfiles/file/xubowigivubedis.pdfIn PDF document text
    • https://pediatricpotentialsnj.com/PP/PPpng/files/38065984483.pdfIn PDF document text
    • http://acupunctuuryao.nl/ckfinder/userfiles/files/fetilawajegaleba.pdfIn PDF document text
    • https://tectrongim.com/uploads/file/wipesixuxelalunugu.pdfIn PDF document text
    • http://planet-for-events.de/userfiles/file/83285755845.pdfIn PDF document text
    • http://www.astmalek.cz/obrazky/file/31329184323.pdfIn PDF document text
    • https://sibois.eu/userfiles/file/fadilesofoxuri.pdfIn PDF document text
    • 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_off0000e4b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4B5 10788 bytes
SHA-256: c4326d4c5d150bd40668f85d069ccb44d7d0487bdf0013a789095cac484f4107
font_01_sfnt_off0000fdb2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDB2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000115c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115C4 18668 bytes
SHA-256: 0b708f1244aed75c204d713a22946dfab4a81af739903b40537c0a9f630ee553