Malicious PDF — malware analysis report

Static analysis result for SHA-256 b3aca815c08c68e4…

MALICIOUS

PDF

76.5 KB Created: 2021-03-23 08:30:47 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 6b2ebadf3657090ea262cba03fa57207 SHA-1: a829096723c73da8f5a45ebfb61ca5c662f2cef5 SHA-256: b3aca815c08c68e413d72662a5d21db0c78840c4ee66196c949cf4fcf4c8b782
194 Risk Score

Malware Insights

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

This PDF file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan payload. It contains a large number of external links, many hosted on disposable domains, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, appears to be a lure related to educational worksheets, combined with metadata from wkhtmltopdf, indicating it was likely generated programmatically to appear as a legitimate document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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 contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://zajinet.ru/123?utm_term=subordinating+conjunctions+worksheet+free PDF link annotation
    • https://cdn.sqhk.co/vepanoxubere/iduEcid/classifying_chemical_reactions_worksheet_page_9_answers.pdfIn PDF document text
    • https://cdn.sqhk.co/jifigetuxu/dPHjdQW/toralev.pdfIn PDF document text
    • https://rawoxozuk.weebly.com/uploads/1/3/2/6/132695352/mapinuwew.pdfIn PDF document text
    • https://cdn.sqhk.co/gusoguribus/WKonhet/95957614493.pdfIn PDF document text
    • https://cdn.sqhk.co/vezubusevof/ggAqVif/chyawanprash_arjun_kapoor_song.pdfIn PDF document text
    • http://modozadubop.mywebcommunity.org/bibelot_dfinition.pdfIn PDF document text
    • https://cdn.sqhk.co/woteruzid/QWHhcY5/road_champs_1987.pdfIn PDF document text
    • http://wuramegojuluz.mywebcommunity.org/tabla_de_alimentos_ricos_en_fibra_soluble.pdfIn PDF document text
    • http://tunewejewuz.mypressonline.com/muvakujovudoliz.pdfIn PDF document text
    • https://misapunuzure.weebly.com/uploads/1/3/1/6/131606411/d9ac32e043.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://bb74f61c-7045-47bf-9a7e-968101ee373e.filesusr.com/ugd/81ef4b_8c605dedaa874d7aa787d9ab4f13e679.pdf?index=trueIn PDF document text
    • https://40fd9d30-e691-4ad4-9ff9-7de67b304886.filesusr.com/ugd/45b27a_e981c05ce88f47e0915ba86f386e8836.pdf?index=trueIn PDF document text
    • https://45180a89-8b92-4d54-a4c6-cdf0ad6af3c7.filesusr.com/ugd/2b98a3_43c7644a2c4f487b88830dd51d9cd94a.pdf?index=trueIn PDF document text
    • https://528a8416-53f4-4693-bcf0-540471887af1.filesusr.com/ugd/c3aa89_906e74e64bf94d29bfe8e3fc145f196e.pdf?index=trueIn PDF document text
    • https://e6f9d1db-9bad-45ba-a188-0e8e378e8087.filesusr.com/ugd/99b222_57bef84fe4fd4371865eb386131a9c0c.pdf?index=trueIn PDF document text
    • https://29ca30ec-7ad4-487f-8637-d2d67f3a323c.filesusr.com/ugd/10b11f_9af42c8837cd41409784868d5ebb8770.pdf?index=trueIn 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dda6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDA6 5608 bytes
SHA-256: 6919d1f1ce5de1f48fab51dbf57cefae5d19b0d9de79a1e0b8ffc913926615bd
font_01_sfnt_off0000f0bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0BF 11136 bytes
SHA-256: 4bd8ea53f9eb137d772f29664aa08915075aa4d97a75fc51768b61736a185ca4
font_02_sfnt_off000116be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116BE 4324 bytes
SHA-256: 05d2457133b820fa77aa358e30e9acfbad3f04c46ced9a37296d9311117db176