Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f639df4d2c2db4f…

MALICIOUS

PDF

89.5 KB Created: 2021-03-29 02:03:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-02
MD5: 4652b79695ac480c756913fa90b7f5c6 SHA-1: 32ef0db78e968bc3a058adadd6048c9245c7cc4f SHA-256: 3f639df4d2c2db4fb6255d437e98779b7c7e59415d9a0fb93f34683fe5d5f288
186 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, specifically identified as a phishing trojan by ClamAV. It contains a large number of external links, many hosted on disposable domains, indicating a link farm designed to manipulate search engine results or direct users to malicious sites. The embedded document body, though heavily corrupted, contains metadata suggesting it was generated by wkhtmltopdf, and the presence of numerous external URIs points towards a phishing or SEO spam attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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/award?keyword=mathematics+book+pdf+for+class+8 PDF link annotation
    • https://sonujeti.weebly.com/uploads/1/3/0/9/130969686/xomuk-vuwoduzo-sarabusidut-dimet.pdfIn PDF document text
    • http://dapurixid.sportsontheweb.net/treatment_of_attrition_of_teeth.pdfIn PDF document text
    • https://cdn.sqhk.co/motanunika/gd2yhdd/g_switch_2_game_online.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4468259/normal_5feb908d59a02.pdfIn PDF document text
    • https://cdn.sqhk.co/dugelabomaw/mKpSMCn/papeguputudi.pdfIn PDF document text
    • https://vaxurubezinijor.weebly.com/uploads/1/3/4/6/134690270/mubuxiriwutos.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4464527/normal_5fe8829351c7b.pdfIn PDF document text
    • http://fastpeysistem.online/how_to_reset_a_westinghouse_tvkkklc.pdfIn PDF document text
    • https://fukikabigo.weebly.com/uploads/1/3/4/4/134457586/66e82aaa658.pdfIn PDF document text
    • http://pitushok.fun/weight_loss_diet_chart_for_female_vegetariancz2nb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4420915/normal_5fd643bf5f496.pdfIn PDF document text
    • http://kimiter.medianewsonline.com/69813022232.pdfIn PDF document text
    • https://tipuzivi.weebly.com/uploads/1/3/0/9/130969377/6829415.pdfIn PDF document text
    • https://pukakiliratof.weebly.com/uploads/1/3/4/7/134768090/peviguzame.pdfIn PDF document text
    • https://xipumizi.weebly.com/uploads/1/3/4/7/134746986/rotejadoleg.pdfIn PDF document text
    • http://myluckybet.xyz/natural_disaster_management_notesm50ar.pdfIn PDF document text
    • https://nefitajufu.weebly.com/uploads/1/3/4/7/134712437/jebefagewaxeruzuz.pdfIn PDF document text
    • https://wizisenax.weebly.com/uploads/1/3/4/3/134320615/sejupas.pdfIn PDF document text
    • https://filukekab.weebly.com/uploads/1/3/4/4/134478490/tewewogusedo.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4428062/normal_602970370a186.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4381978/normal_603572fd93574.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
    • 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_off000111a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111A7 5480 bytes
SHA-256: 99096c024e17289432fdf262e979ec901db46c759fcb191218db81deb13cc0e7
font_01_sfnt_off0001243b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1243B 11192 bytes
SHA-256: 81e9c41f344727014aaeec0595cf99a1c16e0da31e1cda81e3e10c35510fe7b1
font_02_sfnt_off00014a82.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14A82 4324 bytes
SHA-256: 7f6049e5011acf0e8581793f2bc2bb947aac2929fdb77abc318b2a6155c1ef71