Malicious PDF — malware analysis report

Static analysis result for SHA-256 d79471bacfd951e0…

MALICIOUS

PDF

79.8 KB Created: 2021-04-16 01:27:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 1ea5a0863f367aba166427565a7a7033 SHA-1: 21830e4ede8dd86de7e8ea2c76d0cd9726603ce6 SHA-256: d79471bacfd951e0e679c53ebf9ecb9b7425f0bcd7d755de9bcd9f79ded72c61
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to disposable hosting, indicating a link farm or SEO poisoning tactic. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware delivery via the embedded URLs. The document body, though heavily obfuscated, suggests a lure related to 'similar triangles worksheet answers'. No scripts were extracted, but the PDF structure and external links are indicative of a malicious campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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://xajibur.ru/strik?utm_term=7.3+similar+triangles+worksheet+answers PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4373271/normal_6061372951dea.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4471236/normal_5fede9519c158.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4403948/normal_6046bec263528.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4477626/normal_5fe25d97d6cb1.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485689/normal_600026ae3bcc2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4414501/normal_5fd87acb6c8ef.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4377931/normal_6025b108dba7f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4461485/normal_603cb7dc29454.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://f59c0a4d-c104-43ac-8966-a5978cdf1b8c.filesusr.com/ugd/0c1ebd_e779a689e636494e876a5fbbe8483e3a.pdf?index=trueIn PDF document text
    • https://4cf2acc4-d143-4013-a78d-f21de0873c4f.filesusr.com/ugd/e4636f_09f44847d73e413bbd651f6b095fe951.pdf?index=trueIn PDF document text
    • https://ce322291-b3da-4cc2-ae0f-523e25daec44.filesusr.com/ugd/4530da_d29afd3f491a40a8bbeb5f1b5771a133.pdf?index=trueIn PDF document text
    • https://b1fdf235-84a1-4479-ba44-7fc4a4f983d7.filesusr.com/ugd/afcd87_4ec30220aefa473fbc298c450b116f74.pdf?index=trueIn PDF document text
    • https://ad0d0dbb-669b-46a9-85df-79487014a0f3.filesusr.com/ugd/00d95d_f999a15fcc2e416a9a4c30bd30865d20.pdf?index=trueIn PDF document text
    • https://2f2ab42d-e0b4-4bd3-aa50-2430da1ff5fc.filesusr.com/ugd/eaf48f_a6bdc9e2778f49bd803c8ec7e9d2254a.pdf?index=trueIn PDF document text
    • https://8c4778c4-ed17-4cf1-86f9-5448e21c5c15.filesusr.com/ugd/6da380_5bcd27dd99c84c47a3c1f4bf87b7319e.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/290ca6b8-7dd8-4cac-b3aa-c6bcea48b1f0/whats_the_difference_between_hero_7_white_silver_and_black.pdfIn PDF document text
    • https://8eefcaf3-52f5-4123-8be5-b1f0aaeea45e.filesusr.com/ugd/1d3654_30e828d601d340d4bfda16f49e854228.pdf?index=trueIn PDF document text
    • https://cd29ef07-728f-4a0b-b57b-23e770395c36.filesusr.com/ugd/f14cf6_9df2232ec2884bb48468425577c8d47f.pdf?index=trueIn PDF document text
    • https://091a8774-b5bd-4fb7-8799-8d1ca0ca44ad.filesusr.com/ugd/8716ab_121c9adfd725430cb2f0c28dc0163922.pdf?index=trueIn PDF document text
    • https://920f4c01-5fd6-4c40-8b27-b99972fecb60.filesusr.com/ugd/d63aaf_5cadc1ff5a594c48abc9990d7c7fe421.pdf?index=trueIn PDF document text
    • https://6478d21b-237c-41b5-add8-96d7b9819624.filesusr.com/ugd/c7ef1a_a095d0c27b3745718155a1239916ae8f.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/906a8285-c698-4172-ae33-e2d1b4d597f7/37979704609.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
    • 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_off0000e382.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE382 5436 bytes
SHA-256: 865a12c4619ee60c77ab59b00a17b9b87c84e5a34e46f3f9777540cd7b89f24b
font_01_sfnt_off0000f5f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5F3 10976 bytes
SHA-256: b1000858568c3a58059fe578649ec0ff1318f8f2e725de93bbbc8bc8d8c6f4e4
font_02_sfnt_off00011bd0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BD0 16240 bytes
SHA-256: cb3a116f65d595051672184d3248447d15bca29c90c5e9765e9bd0c4dcc34512

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