Malicious PDF — malware analysis report

Static analysis result for SHA-256 fc8c421f12beabc7…

MALICIOUS

PDF

82.7 KB Created: 2021-05-09 11:40:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: a1093b0e1759a7b899df16f518652d0e SHA-1: 20fbd66ab7c52e2f76d43ab23e4e1ce88afea861 SHA-256: fc8c421f12beabc7d20e7a1627b00446c03b5e5a46245c414ce61e7e9d9b1d8c
186 Risk Score

Malware Insights

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

The PDF file contains numerous external links, identified as a link farm, with a primary URL suggesting a lure for homework answers. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or SEO spam. Although no scripts were explicitly extracted, the PDF structure and embedded URIs are indicative of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://pelibifir.ru/strik?utm_term=algebra+textbook+homework+answers PDF link annotation
    • http://bowemesuzot.iblogger.org/what_are_the_principles_of_health_economics.pdfIn PDF document text
    • http://bepelisufozasep.mywebcommunity.org/mopezulexaxemawitapida.pdfIn PDF document text
    • http://rapoxarawiwalo.sportsontheweb.net/94582839808.pdfIn PDF document text
    • http://gofadivus.mygamesonline.org/bad_public_relations_examples_2020.pdfIn PDF document text
    • http://pukitifafizeba.mywebcommunity.org/bingo_sheets.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://d1e6aceb-f258-402f-b59e-92ecb386693c.filesusr.com/ugd/2cc58f_9dec3ce367a34a718d20b4e2785bd979.pdf?index=trueIn PDF document text
    • https://46b09160-81f9-4cb3-9cca-f7b5b0c0229e.filesusr.com/ugd/179cc6_b10a0482c56843a2b09f4d00440b6189.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/waduzirader/68083128755.pdfIn PDF document text
    • http://tituroxir.rf.gd/vodipibomibebatit.pdfIn PDF document text
    • https://bf6af823-cb0d-4ee8-9d5b-4f0b1de5ed24.filesusr.com/ugd/9eb187_710932b61578434d8daac8c3351e5bea.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/nufidibodudulad/79693836498.pdfIn PDF document text
    • https://6c71f620-b6e5-46cc-9e58-526c5f0a7a41.filesusr.com/ugd/1c90dc_01439184888945869403609c87751495.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/minaxigevani/this_is_water_video.pdfIn PDF document text
    • https://f38be386-5799-403b-9303-fb121113655a.filesusr.com/ugd/6f1aa7_ad69849f30f9495c8e5bfd58cfe13180.pdf?index=trueIn PDF document text
    • http://ranitirunom.myartsonline.com/addendum_agreement.pdfIn PDF document text
    • https://625f08e2-3d8e-45b5-8e8c-b95d001c5c7c.filesusr.com/ugd/d94ae5_f66af7b2b5f24ec38960e9e64a61388d.pdf?index=trueIn PDF document text
    • https://b1c30c75-ab46-439a-884d-3836ae4b8a49.filesusr.com/ugd/2d1648_3b67961e45564d3bb4128ae33ef62171.pdf?index=trueIn PDF document text
    • https://a1d3e036-d9a1-4be1-9d2f-eedbb581cb22.filesusr.com/ugd/3ce946_5b65c263424a487aa2a4bb9e2c28b10f.pdf?index=trueIn PDF document text
    • http://jifujurudale.epizy.com/bexavonulitopake.pdfIn PDF document text
    • https://s3.amazonaws.com/xopugup/lofagijirezeluveni.pdfIn PDF document text
    • https://b73b9701-b1df-43be-b031-73419f87697c.filesusr.com/ugd/bfbd96_d260e384836e4b6c80979c660328cdd2.pdf?index=trueIn PDF document text
    • https://0e67983c-e844-40c9-b604-97311ec94efe.filesusr.com/ugd/6e13d9_2c66cb059e614fa49a3ecdbb780631ee.pdf?index=trueIn PDF document text
    • http://retelikejajego.rf.gd/nitazadogamagagok.pdfIn PDF document text
    • https://ddb281da-11d2-423e-b83a-408ecf1f607f.filesusr.com/ugd/9db61c_16e30abf76924ba382857bec8059f382.pdf?index=trueIn PDF document text
    • https://88749095-6fd7-453f-8e8a-15b48fe47dd1.filesusr.com/ugd/e4d7df_7b77a9cfc6564883ac7278d21397bb74.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_off0000f2d6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2D6 5192 bytes
SHA-256: d0f0202737263af18a6ace5366dcc980ffa85e069f46e11e0a777fa6894bda03
font_01_sfnt_off00010466.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10466 11892 bytes
SHA-256: b29b1b264b2da82648f32330a9f4d047dbd0bd82fd96cb1d1566815fae81b1aa
font_02_sfnt_off00012cfe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12CFE 4324 bytes
SHA-256: 05d2457133b820fa77aa358e30e9acfbad3f04c46ced9a37296d9311117db176