Malicious PDF — malware analysis report

Static analysis result for SHA-256 8cf81565c948bc8d…

MALICIOUS

PDF

84.1 KB Created: 2021-04-01 03:29:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 0ba66d9fde9d0eee08874ccbe0cf3442 SHA-1: c9c7b6a37872577c31a9b0b9b39458fddd69e73c SHA-256: 8cf81565c948bc8d9d8fb4fd21fb74fa211777c408730b1d8295b2e4a4141ff1
186 Risk Score

Malware Insights

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

The PDF file contains numerous external links, many pointing to disposable hosting, and is flagged by heuristics as a link farm and potentially malicious. The ML classifier and ClamAV detection strongly indicate malicious intent. The embedded URL and the nature of the link farm suggest an attempt to redirect users to malicious sites, likely for phishing or to download further payloads.

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://jottigo.ru/wix?keyword=glycolysis+and+krebs+cycle+worksheet PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4491169/normal_60560afe4fcb9.pdfIn PDF document text
    • https://tesiligozi.weebly.com/uploads/1/3/1/4/131407846/puzuwaj.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4371809/normal_5fe9f8674a2f8.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4366366/normal_5fcefdd0c5d33.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369504/normal_605283012a880.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4376598/normal_604e9b97cff38.pdfIn PDF document text
    • https://sanijala.weebly.com/uploads/1/3/4/8/134889677/fijapikigu-teronas-jifugetetibet.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/midipes/guided_meditation_for_creativity.pdfIn PDF document text
    • https://s3.amazonaws.com/jasipefulaxiduj/xanufem.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c22a7cfe-7eca-4cf1-b116-f932897473ce/which_countries_fall_in_tropic_of_cancer.pdfIn PDF document text
    • https://63b1f34b-4847-450f-8d9a-4788d10e1cf5.filesusr.com/ugd/451a43_918421ccc54947e7a12f770a7e1a9994.pdf?index=trueIn PDF document text
    • https://9e2bb560-353e-4f5d-a08b-1363560edab4.filesusr.com/ugd/6c032c_60a9268606f24d618998b01977f47ac6.pdf?index=trueIn PDF document text
    • https://c8070bf9-ed42-4c5d-8eb8-ca35ee70f136.filesusr.com/ugd/d38238_8c4d9af826e14c9b9ef6dec99342d914.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/4af7730d-8025-45f3-beb4-6c6f94a9bb88/20802049399.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d511f7d8-2cb8-4ae7-8fa6-7b78527d4a7c/4653662067.pdfIn PDF document text
    • https://s3.amazonaws.com/lekezaru/wujozuvubunokunaxizela.pdfIn PDF document text
    • https://0dc5016f-38c0-4e11-84f4-4717e3ef4ec7.filesusr.com/ugd/4fd84c_ce203061686a417e8ef5665c0c780e48.pdf?index=trueIn PDF document text
    • https://b5526579-b22d-45a0-8251-9885a72cf3eb.filesusr.com/ugd/0cd019_3daf10d5a085435a934cd67435b3854f.pdf?index=trueIn PDF document text
    • https://0e098354-e5d1-4afc-9be7-763a70ae5e44.filesusr.com/ugd/ef253e_3396125579204467aea2a75ee7a09a2c.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/xefezesebusu/lubepuguj.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
    • https://savannah.gnu.org/projects/freefont/In PDF document text
    • http://www.gnu.org/licenses/In PDF document text
    • http://www.gnu.org/copyleft/gpl.htmlIn 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_off0000fbad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBAD 6440 bytes
SHA-256: 705377623a4c4344e02470fedf876d1ed6f0c7c0eac322cafb15afc9430d14bf
font_01_sfnt_off00010ba1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BA1 5456 bytes
SHA-256: c64bcbfeaa84a38b5736678bbd1288db81697279831bb7e255bdd5707d3a8046
font_02_sfnt_off00011e45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E45 10620 bytes
SHA-256: f5610523b09887e00ae4ccc3d35efded9db8e331b2f0d4f0c1ec69dc48d6bf25