Malicious PDF — malware analysis report

Static analysis result for SHA-256 84e1c5cf1d49f52b…

MALICIOUS

PDF

70.7 KB Created: 2021-03-16 06:14:18 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-13
MD5: 94df91640dc9814cb46464ba2d521e9c SHA-1: 0df3da7c31af1b606b4b414364eefe5affa01a2c SHA-256: 84e1c5cf1d49f52bb4cdd3d4571648d98a6ed233cb0193827bc70c713127a9da
206 Risk Score

Malware Insights

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

The PDF contains multiple heuristics indicating it's a link farm, with a critical finding for PDF_SEO_LINK_FARM and PDF_SEO_DISPOSABLE_LINK_FARM. It embeds external URIs, including one pointing to 'pelibifir.ru', suggesting a phishing or SEO spamming campaign. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to distributing further malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 7

  • 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.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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/123?utm_term=landforms+and+bodies+of+water+worksheets PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4446789/normal_604c99502321b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4528959/normal_6041872fabb7a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4455370/normal_602e4c7e418a4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4402706/normal_601b2abaecd34.pdfIn PDF document text
    • http://fullhp.info/woods_tents_set_up_instructionspbamg.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4379500/normal_5ff4caf7a1f3f.pdfIn PDF document text
    • http://olipaka.xyz/janusaguxakikixuvuzelihtgga.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4405186/normal_600fece9127f9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4502175/normal_6013bfa26bf9b.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4465398/normal_5fc772c65f96c.pdfIn PDF document text
    • http://igafnd.org/kamukikofimamiduleg9va5d.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485010/normal_5fc6746ad4f89.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4471235/normal_5fc79b23986a1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4487007/normal_5fd61e71214ef.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4484156/normal_5ffd481c3540d.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4466676/normal_6003b26fe4d56.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4409992/normal_6020a9af18e93.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/xutomoxu/xowonoromubiga.pdfIn PDF document text
    • https://s3.amazonaws.com/gopuze/atherosclerosis_slideshare.pdfIn PDF document text
    • https://s3.amazonaws.com/daniwodug/viking_appliance_repair_near_me.pdfIn PDF document text
    • https://s3.amazonaws.com/mavixu/kiwofalesixojarotif.pdfIn PDF document text
    • https://ed21222e-fee3-4fab-8b52-e2ddb7bb35ab.filesusr.com/ugd/e73fea_1fecada76d2c41ce90a1689dc6dd30dc.pdf?index=trueIn PDF document text
    • https://d71fc03c-aea6-48f7-a990-8afffb22108d.filesusr.com/ugd/3de8a6_9d81a1649b124792ac179c2e613ffa9c.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d8e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8E3 5352 bytes
SHA-256: 5ebcdb6dfcb473c7bd3823034ee3bd5d1c3a6eb6625f9b77abdb04c0639177e6
font_01_sfnt_off0000eb03.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB03 9816 bytes
SHA-256: 7be1ef3b2ecedfaeee9f8b600457c8bc8fb932aeedefd6bd27a86ceb0ec7e56b