Malicious PDF — malware analysis report

Static analysis result for SHA-256 af821a5643b9fb75…

MALICIOUS

PDF

81.4 KB Created: 2021-09-09 09:38:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 38017cf6de487c3549ee1b2ffb12509b SHA-1: ea0a373008f6635f6a05071e52e3ac9411657d03 SHA-256: af821a5643b9fb75f6bdaebf1c18c9ff97304dfeba40d2a80cdee7dee1a30e70
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The PDF contains numerous embedded links, many pointing to external PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically flags this behavior. While no scripts were explicitly extracted, the nature of the embedded links and the overall detection suggests it is designed to lead users to malicious content, likely phishing pages or malware downloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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
  • 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://evpltravel.com/xv_image/file/15645498208.pdf In PDF document text
    • https://llibreriaha.com/img/events/file/80064180061.pdfIn PDF document text
    • http://www.putnamtaxi.net/wp-content/plugins/formcraft/file-upload/server/content/files/16137d3c9639f9---5960010780.pdfIn PDF document text
    • http://www.mezmat.ru/ckfinder/userfiles/files/17563643136.pdfIn PDF document text
    • http://archetipoingegneria.it/userfiles/files/24070298247.pdfIn PDF document text
    • http://ckrestaurantgroup.com/ckfinder/userfiles/files/bojajenefiga.pdfIn PDF document text
    • http://capesociety.ca/uploads/files/62343492616.pdfIn PDF document text
    • http://physio-praxismitte.de/userfiles/xamututul.pdfIn PDF document text
    • http://carzip.biz/files/uploads/files/pevaluden.pdfIn PDF document text
    • https://stomatoloska-ordinacija-rijeka.com/files/2947232733.pdfIn PDF document text
    • http://quranday.org/userfiles/file/66086870059.pdfIn PDF document text
    • http://www.waetsukai.jp/system/ckfinder/userfiles/files/54921894444.pdfIn PDF document text
    • http://carrozzeriabosini.net/userfiles/files/87779949049.pdfIn PDF document text
    • http://accessiblevehicleservices.com/userfiles/file/fatilelofas.pdfIn PDF document text
    • https://oldd.adventurenetbg.com/userfiles/file/noveniware.pdfIn PDF document text
    • http://jysfh.com/upload_fck/file/2021-9-4/20210904015014307119.pdfIn PDF document text
    • https://xn--49st2et51duvk.com/upload/files/71688156040.pdfIn PDF document text
    • http://qdxqw.com/uploadfile/file/8357800785.pdfIn PDF document text
    • https://uleshuzataruhaz.hu/files/file/26588019456.pdfIn PDF document text
    • http://we-women.de/default/files/uploads/file/50812663582.pdfIn PDF document text
    • http://snft.ro/media/file/26920414092.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=voice+chat+apps+for+androidPDF 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_off0000da25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA25 10640 bytes
SHA-256: de87573abb1ffa889072961e6bca448baf7b89a84650ad1b47a9a584948771af
font_01_sfnt_off0000f278.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF278 17628 bytes
SHA-256: 87cabc1f22d944d5a2f23684149bdcd02e82f12f025a8f5da70f1c8e45fd9cc3
font_02_sfnt_off00012006.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12006 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1