Malicious PDF — malware analysis report

Static analysis result for SHA-256 da4458e6ce146b3e…

MALICIOUS

PDF

77.3 KB Created: 2021-03-13 16:18:21 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 37ee7c0acd71f763e4cb526b73f95768 SHA-1: 0a365ca3dfa621141e9856e5c33bccf92bf90ce5 SHA-256: da4458e6ce146b3ea037cb6a7d0f89169548c1952d5b247c7f699be2022443ae
126 Risk Score

Malware Insights

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

The PDF contains embedded URLs and is flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. The document body, though heavily obfuscated, suggests a lure related to academic research ('Bacterial cell wall polysaccharides pdf'). The presence of numerous external links, including one to 'pelibifir.ru', indicates an attempt to redirect the user to a malicious site, likely for credential harvesting or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • 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 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=bacterial+cell+wall+polysaccharides+pdf
    • https://begiruxuvasepi.weebly.com/uploads/1/3/5/3/135351124/1827838.pdf
    • https://dobetabuzaduguz.weebly.com/uploads/1/3/5/3/135312815/b4904.pdf
    • https://static.s123-cdn-static.com/uploads/4465402/normal_5fefc7ef8df41.pdf
    • https://static.s123-cdn-static.com/uploads/4365567/normal_5fcb03d56a0f4.pdf
    • https://static.s123-cdn-static.com/uploads/4416669/normal_5fddaaaf4d71b.pdf
    • https://cdn-cms.f-static.net/uploads/4462694/normal_6015692728fc1.pdf
    • https://fabexitib.weebly.com/uploads/1/3/4/1/134109013/vatog.pdf
    • https://cdn-cms.f-static.net/uploads/4450356/normal_600a5e0153f04.pdf
    • https://rixagaxovexi.weebly.com/uploads/1/3/4/0/134000332/tigobifosovek.pdf
    • https://cdn-cms.f-static.net/uploads/4448113/normal_601b1022340cb.pdf
    • http://kaxunatinoti.iblogger.org/spaceship_away.pdf
    • http://raxijulerejo.iblogger.org/81381056815.pdf
    • https://cdn-cms.f-static.net/uploads/4464323/normal_60396d0ceed7f.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/wamatasamegu/jobekakafatefotivajaxipa.pdf
    • http://dumudolaba.epizy.com/vadifivozojulinuxunemetod.pdf
    • http://soxosodazafu.epizy.com/xoruwosavulolefages.pdf
    • https://s3.amazonaws.com/dezajok/99794088330.pdf
    • https://s3.amazonaws.com/ronatiduzoxij/decomposition_of_hydrogen_peroxide_experiment_lab_report.pdf
    • http://duxurulokij.epizy.com/afro_beats_2019.pdf
    • https://s3.amazonaws.com/votubukaxogilix/estimating_sums_and_differences_4th_grade_worksheet.pdf
    • http://pabaxonewopux.epizy.com/kupaxujejakogaf.pdf
    • http://kosugib.epizy.com/how_to_install_air_conditioner_unit.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f23f.bin
be0ff9d1d7e226375c9d127eaf6621706551a6e0961666ee57daa50087b255ac		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF23F 5484 bytes
font_01_sfnt_off000104f8.bin
505276d2a204550f2316f78c291d9d0ddc88c88dfc13f793022732b7bbe90af9		 pdf-font-stream PDF embedded font (sfnt) at offset 0x104F8 10204 bytes

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