Malicious PDF — malware analysis report

Static analysis result for SHA-256 4407836ea7cf641c…

MALICIOUS

PDF

71.9 KB Created: 2021-03-30 13:30:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-13
MD5: a0c6cc0f91eede4d759540ec7e808b7b SHA-1: da9579e7b011d132d5f39e8d1a7ee7707bc2ad21 SHA-256: 4407836ea7cf641c5adb9d3bcea9e0852cce3e1e67e756889fca7f3d36a3d257
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high probability of malicious intent. Heuristics reveal it functions as a link farm, containing numerous external URLs, with a critical finding of it being a 'PDF_SEO_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM'. The primary external URL observed is https://jacksth.ru/123, which is likely part of a phishing or SEO spam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://jacksth.ru/123?utm_term=angular+mat+input+date+format PDF link annotation
    • http://steelsho1.club/semuxizodiresepujapunamkdo3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4390366/normal_5fe9d817eca89.pdfIn PDF document text
    • http://dfwshootersupply.com/70790349048q2e1e.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4380384/normal_5fdf3d044e6ba.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4407810/normal_5ffb54f95c903.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496585/normal_5fe8e5ecb0567.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4409405/normal_5fe7fc7cb6a7a.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://19a4122d-28db-4ec2-a9e3-8c1e87f24dd5.filesusr.com/ugd/70d0b7_0c8599f3222d4dd4ad0699a1095d6839.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/1bc6278f-325b-4520-a76e-36af478d2363/peer_gynt_suite_1_movie.pdfIn PDF document text
    • https://71a0d42b-91d5-4e94-9338-ff69ca8a624b.filesusr.com/ugd/e5d5e5_bead45645838405daabff04ab5a9248d.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/322ff99a-3206-462a-a017-b1b4923f3ae2/why_wont_my_karcher_window_vac_work.pdfIn PDF document text
    • https://s3.amazonaws.com/feliso/xomujiribuvore.pdfIn PDF document text
    • https://s3.amazonaws.com/fusidejebi/juxebezojivo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b5c90c72-f288-4119-8651-dbb7df3b1371/54161411132.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3a3159eb-2922-4160-841d-11942a27513a/levujexer.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/84576722-deba-43e4-ba71-157a494b6d32/conversor_g_l_a_mg_dl.pdfIn PDF document text
    • https://s3.amazonaws.com/roxawo/duplex_2205_stainless_steel_sheet.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/36d0fe5b-a1be-4b6e-9156-66168a1cbcd0/ledabozejetuzegid.pdfIn PDF document text
    • https://cf075d60-af7c-4c71-a16c-5c8c125a9bb7.filesusr.com/ugd/cc03df_201e30fdf0f64e6c8c0360edcc833cd4.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/54d2d32d-f7c9-425b-9fee-435d3d37e40f/89313238511.pdfIn PDF document text
    • https://s3.amazonaws.com/zodawanuror/audit_trail_report_template.pdfIn PDF document text
    • https://s3.amazonaws.com/zedilegol/nurofixufeled.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b6f0c1bc-4e13-4c5c-a5bf-62cca560ded7/28516748453.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_off0000da7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA7D 5172 bytes
SHA-256: a982e0589ceebc9b5019e61718a504d4533158e64282308e03aeadaf64bd719b
font_01_sfnt_off0000ec04.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC04 11168 bytes
SHA-256: e737feab8e69ed0012506b4d05deaa0a14a900a91ff2a82045c475a41f58269b