Malicious PDF — malware analysis report

Static analysis result for SHA-256 a0aa9985725d1f5e…

MALICIOUS

PDF

79.0 KB Created: 2021-09-16 21:07:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f87a6b19240400d9c65c247837eff725 SHA-1: 244fae879b317aa903dd51cd4595779b23e297f5 SHA-256: a0aa9985725d1f5e70b36f85b0197c0b75aad7b882347cb717c4a1641c43b47b
126 Risk Score

Malware Insights

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

The sample was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many pointing to PDF files on various domains, suggesting a link farm or redirection mechanism. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM indicates a high number of distinct hosts and links per host, reinforcing the malicious intent of directing users to potentially harmful content. No scripts were extracted, but the PDF structure itself is leveraged for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://flexinform.com/hirlevel/file/57732362843.pdf In PDF document text
    • http://homeopathyhongkong.org/files/34677379137.pdfIn PDF document text
    • https://www.hkha.com.hk/ckfinder/userfiles/files/8472235643.pdfIn PDF document text
    • https://techson-cctv.com/upload/file/zebakexapegedajasi.pdfIn PDF document text
    • http://www.tobywells.org/media/fckdir/file/roredumowivo.pdfIn PDF document text
    • https://petrovsky14.ru/docs/files/56808066066.pdfIn PDF document text
    • https://chrmglobal.com/userfiles/file/voboxa.pdfIn PDF document text
    • http://honderhotel.com/UploadFiles/FCKeditor/20210904200121.pdfIn PDF document text
    • http://www.andreapondika.cz/file/18357224509.pdfIn PDF document text
    • http://fratellilongoni.com/userfiles/files/4651500859.pdfIn PDF document text
    • http://miyozenemeryville.com/uploads/files/59713791083.pdfIn PDF document text
    • https://megashina24.ru/files/files/fajelavepeveguvomosokifun.pdfIn PDF document text
    • https://www.oasipizza.it/wp-content/plugins/formcraft/file-upload/server/content/files/1612f0661a6625---fafediribeleladumakunujik.pdfIn PDF document text
    • http://kpghomerepairs.com/uploads/image/files/perinamun.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/pigisa.pdfIn PDF document text
    • https://infotechb2blite.com/bot/ckfinder/uf/files/xafakoxadafit.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/3t7qcejb9s6dqsph3rqfif9rs7/moramu.pdfIn PDF document text
    • http://abwvictory.com/uploads/files/fibavozenarerulokezevid.pdfIn PDF document text
    • http://bocghebinhduong.com/media/ftp/file/26864447645.pdfIn PDF document text
    • http://rustproofingottawa.com/userfiles/file/dulavukanupapu.pdfIn PDF document text
    • http://brixtontaxi.com/survey/userfiles/files/pewej.pdfIn PDF document text
    • http://digifast.cz/userfiles/laxonuporifetazibumirujo.pdfIn PDF document text
    • http://www.tecnologycenter.com/admin/uploaded/fck/file/wekotavitikabulasirukaj.pdfIn PDF document text
    • http://ebiocell.com/uploadfile/file///2021090610162732.pdfIn PDF document text
    • http://ucg-eg.com/userfiles/file/9008005249.pdfIn PDF document text
    • http://fc-junajted.com/upload/datoteke/jedosiwizudawiwefo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=gta+5+online+download+free+for+pcPDF 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_off0000d0f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0F7 17240 bytes
SHA-256: 8c975a0b92e72e3de3d9af805a4b3850c532e7d700dda622b0aebf14c07d2108
font_01_sfnt_off0000fda5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDA5 10704 bytes
SHA-256: d57208d9082571b2063be0d95afbba610017deab0ec7ed232f358f98140ba2b7
font_02_sfnt_off0001166e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1166E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1