Malicious PDF — malware analysis report

Static analysis result for SHA-256 bbbf5f73622489b5…

MALICIOUS

PDF

86.2 KB Created: 2021-05-06 20:42:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: d2e825395088de5532107816f36f6270 SHA-1: 9c0c9b49426590b0825144875d7a885c666ffb95 SHA-256: bbbf5f73622489b58bd84e283207fbd3b542854f1feca2a490bb629b44e18012
186 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

This PDF file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm or phishing operation. The document body, though heavily obfuscated, appears to be a lure related to 'writing skills', directing users to external URLs like 'https://zajinet.ru/strik?utm_term=how+to+learn+good+writing+skills'. No scripts were extracted, but the overall structure and heuristic firings strongly indicate a phishing or malicious redirection attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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.
  • 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/strik?utm_term=how+to+learn+good+writing+skills PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4375703/normal_6004069eeb3bd.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417648/normal_5fd1b7613fe44.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486552/normal_605df61817abb.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4528780/normal_5ff7099f49f44.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4483586/normal_605d87bcdb831.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://204833c8-abda-4421-8777-5048ee7dd919.filesusr.com/ugd/e30b7a_6c3a5aec6651403e8c1625db7d25a554.pdf?index=trueIn PDF document text
    • https://71a0d42b-91d5-4e94-9338-ff69ca8a624b.filesusr.com/ugd/e5d5e5_a4b2e76960124ddf8497d03b1e63d433.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/rumezo/identifying_theme_practice_2_worksheet_answer_key.pdfIn PDF document text
    • https://40052bae-d6b0-4be3-9c84-96956a804c69.filesusr.com/ugd/32907c_3183e0192a284922ac622121e66d304f.pdf?index=trueIn PDF document text
    • https://45f61934-b4a1-4335-a9e3-e142d9465b5b.filesusr.com/ugd/0dd040_ab17ff582afc4e26a6c537418308efb0.pdf?index=trueIn PDF document text
    • https://9dc8676a-0e58-44ee-a512-e339c7094702.filesusr.com/ugd/7c0652_0f3f358b06a84b4ea5233ad646b0fc82.pdf?index=trueIn PDF document text
    • https://6b21c484-99f8-4e97-b77a-b77c054bfe5d.filesusr.com/ugd/f139d4_c7ba3a2c05c04bb99b37d3c02b174761.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/voxipanovigepiv/how_do_desert_animals_survive_the_heat.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001059f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1059F 4900 bytes
SHA-256: 0f253fc7b39ca17092b51da83177e7e4abdbd01f960fbfeeacf9dcb65cf53f8c
font_01_sfnt_off0001165c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1165C 11152 bytes
SHA-256: d817de544ffa654dc744cc6ed44a37e45ac6b8cb0abc44a273df13e022d50d83
font_02_sfnt_off00013c10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13C10 4324 bytes
SHA-256: b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c

Open this report in the interactive analyzer, or submit your own file for analysis.