Malicious PDF — malware analysis report

Static analysis result for SHA-256 f50cbc0823b0c02f…

MALICIOUS

PDF

89.2 KB Created: 2021-05-18 19:43:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: be30f1b2166e3385251d238b23e413b0 SHA-1: d8454659f667879dcdfecf14aefad5f4a89ce4c4 SHA-256: f50cbc0823b0c02f83179c1ecd02b81d8c4d795ee2c7aac8a6e8aa0f57829018
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many hosted on disposable domains, characteristic of a link farm. The document body, though heavily obfuscated, suggests a lure related to 'practice congruent triangles worksheet answers'. The presence of numerous external URIs and the ML classifier's high confidence score indicate a malicious intent, likely to redirect users to phishing or malware sites.

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=4-2+practice+congruent+triangles+worksheet+answers PDF link annotation
    • https://xikematevi.weebly.com/uploads/1/3/4/3/134392378/pekexudigipisogu.pdfIn PDF document text
    • https://subinekole.weebly.com/uploads/1/3/2/6/132695692/kokikepasifibasizok.pdfIn PDF document text
    • https://vifoxofanope.weebly.com/uploads/1/3/4/6/134670603/sirirafo-kuruzupod.pdfIn PDF document text
    • https://widowajezow.weebly.com/uploads/1/3/4/5/134584852/68dc6dc9e281c.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4475565/normal_5ff584785f67d.pdfIn PDF document text
    • https://patewowuxafopon.weebly.com/uploads/1/3/4/5/134595548/tasikosorumef.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453334/normal_606208f037790.pdfIn PDF document text
    • https://budawimimizav.weebly.com/uploads/1/3/0/8/130873912/zebituvudolobiruxiwe.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4385848/normal_5fd967c044741.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496585/normal_6028649161d53.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4413456/normal_600391a0b2ba1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4489607/normal_5fe64bbfc7b3c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4367624/normal_603e2b697eb7f.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4468550/normal_5fcd45617d32f.pdfIn PDF document text
    • https://womizanoxagas.weebly.com/uploads/1/3/1/6/131607010/1232648.pdfIn PDF document text
    • https://buparemekixa.weebly.com/uploads/1/3/0/7/130739227/433a9fe.pdfIn PDF document text
    • https://lonopowixeza.weebly.com/uploads/1/3/4/6/134620564/2801469.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/jigezilor/tasmanian_tiger_reading_answer.pdfIn PDF document text
    • https://s3.amazonaws.com/bejikefowu/classifying_triangles_worksheet_free_printable.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_off0001042a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1042A 5508 bytes
SHA-256: 4b137803cbdfdd925c3553a82ba3a148f46218821a8205df124fa0421a487041
font_01_sfnt_off00011704.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11704 12716 bytes
SHA-256: cdbf3ad67351ca79c31e7952aeccf667fb85fcbe6c49c47dd3e786eb348a7844
font_02_sfnt_off00014149.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14149 16268 bytes
SHA-256: 2bde59aa46d81991958d3429dc06905a4e2379c0c68b6fcf86d4bffe2c5659e9