Malicious PDF — malware analysis report

Static analysis result for SHA-256 b15799b566b94d7a…

MALICIOUS

PDF

76.0 KB Created: 2021-03-27 23:29:11 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 7ed294fce09250b3005d5f3a260722aa SHA-1: da433601973ff9a3ce6a107566c48f803ae9a66d SHA-256: b15799b566b94d7a612e8f82c69bbef79028865ad1860ef97803d0d2bcf7bb8b
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file was flagged by ClamAV as a phishing trojan and ML classifiers indicated a high probability of maliciousness. Heuristics identified external URIs and an SEO redirector link, specifically 'https://nipisod.ru/award?keyword=writing+an+application+letter+for+a+job+pdf', suggesting a phishing lure related to job applications. Although no scripts were explicitly extracted, the PDF structure and embedded URLs point towards a phishing campaign designed to trick users into downloading further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://nipisod.ru/award?keyword=writing+an+application+letter+for+a+job+pdf PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4448357/normal_5fe5915a4468b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4379054/normal_601fd79c515cb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4480387/normal_600d4cffae881.pdfIn PDF document text
    • https://cdn.sqhk.co/zigimovovu/GsRjaRF/happy_friday_and_weekend_fall_images.pdfIn PDF document text
    • http://tisibodonal.22web.org/acmarket_apk_2017.pdfIn PDF document text
    • https://cdn.sqhk.co/zowegifivufo/bDjfIhf/piggy_book_2_release_date_minitoon.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4451940/normal_5ff87d31a49bc.pdfIn PDF document text
    • http://dazipuv.iblogger.org/catecismo_catolico_para_jovenes.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4423700/normal_5ff1167039536.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4381541/normal_603f8bc9a2b11.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4496404/normal_5fcad4fb4b76f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370063/normal_6055a737d0718.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4445333/normal_604b98009c87d.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4530036/normal_5fd06d34823bb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4467561/normal_601a4320bb475.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417040/normal_600d9911c8e9f.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/7d481bb6-0503-44dc-a603-7f65423c3b77/5e_siege_damage.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/07534645-8ea4-4fb6-91a5-0dd2e76b7684/is_there_a_difference_between_a_buffalo_and_a_bison.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7cb5577f-f060-42ae-8fee-d5949521961f/zunisokukarojipuzuvag.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ebbc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBBC 5376 bytes
SHA-256: 6cb446a78cd7ec6cf05dfc5c0707c3f7a41935050a14f61b78b66269d5856e99
font_01_sfnt_off0000fe22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE22 10916 bytes
SHA-256: 6d99cfbf7150d73b6c552acd39db69f71b7504f2c50796167d1d557076e908a1