Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b56b7106e34983d…

MALICIOUS

PDF

76.9 KB Created: 2021-03-11 21:54:46 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: e9f33398a72738faf50d3f839addd49d SHA-1: 0df1d9f5ee4185b939770bce9de25875ea47d2b6 SHA-256: 4b56b7106e34983d1b0ed8099d9030222d69cee55ee3129e39c7bf7ed48f2a47
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by both ML classification and ClamAV, indicating a high likelihood of malicious intent. The file functions as a link farm, containing numerous external links to other PDFs hosted on disposable domains, a common tactic for phishing or distributing further malware. The presence of embedded URLs and the PDF_SEO_LINK_FARM heuristic strongly support this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://leonvi.ru/123?utm_term=aligarh+muslim+university+mbbs+form+2018 PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4488804/normal_5fd7aa32c74e6.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4473916/normal_5fe2c05a92a11.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4414864/normal_6018bd01eb675.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4422371/normal_5febc1a8da978.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4465386/normal_5feda4d07d70d.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://5548a280-a194-4776-8019-0e256783c1fa.filesusr.com/ugd/f2c1dc_39f91fc470e045ab8009ce8856ca84c0.pdf?index=trueIn PDF document text
    • https://1a6c606f-1efd-495f-9370-57f425d809fd.filesusr.com/ugd/1be480_e6af7791c2fd45d1a56a67cc2baa1869.pdf?index=trueIn PDF document text
    • https://ba3a7bb5-edd2-4228-b29c-cf272df6a868.filesusr.com/ugd/bd1c09_5af1acfd8dec4c40b01aab305aa95f76.pdf?index=trueIn PDF document text
    • https://0df6220b-9630-4647-aab6-0d9db69b9d59.filesusr.com/ugd/8b97dd_d4a32cc014e9444ab86a2a1d8abf4a29.pdf?index=trueIn PDF document text
    • https://156bb51f-0b62-477f-88ca-8620af00812b.filesusr.com/ugd/e3ff21_7eeb544dc13c4cdbb2569b5c76a0462d.pdf?index=trueIn PDF document text
    • https://cf336f9a-6a79-4542-9269-5b62d6eb69dd.filesusr.com/ugd/1daf83_9b42b6217ef548d5858c4dbd371926e8.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/tibitexil/vawove.pdfIn PDF document text
    • https://8271b8e8-1520-4b18-8785-2fafc8cd33e6.filesusr.com/ugd/efc97f_8852391c467142f8abaca0dfa0ee7c4c.pdf?index=trueIn PDF document text
    • https://3c3b6f52-20a2-448a-be11-eec5930c502f.filesusr.com/ugd/0ca786_84ff61fde41a45879cf7ffff039ad7f5.pdf?index=trueIn PDF document text
    • https://e0f910ba-f4aa-4d6b-87f6-24d78cda99ab.filesusr.com/ugd/cc15ef_e8d5809dd8c1426292efa7e554f3ffe0.pdf?index=trueIn PDF document text
    • https://6cb1c90e-07cf-4522-b85d-4edd8abc33c8.filesusr.com/ugd/0c41e7_c8fd1e18e461494097d91d29f9fb6793.pdf?index=trueIn PDF document text
    • https://247e77cc-5367-4382-8586-7c5891409f42.filesusr.com/ugd/2dbf5a_915c658859fe48c180aaea7f4be8021d.pdf?index=trueIn PDF document text
    • https://3485775d-af35-4505-8fb4-f6750f575e04.filesusr.com/ugd/42f18e_ef32b3eaafbd44baa1dd175b74d914fa.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/tetofamuxulil/penajazedigiwuzef.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_off0000e9c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9C8 5992 bytes
SHA-256: 6558c7a7b3888bb017065a9d2d33e2290b51818041ee4d330bd5259545c3098a
font_01_sfnt_off0000fe14.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE14 11692 bytes
SHA-256: 290ca6b0e97aec354d2177b49502ab8bb088ef4a76bb8924a66b160beefd782b