Malicious PDF — malware analysis report

Static analysis result for SHA-256 24a181c915ff7640…

MALICIOUS

PDF

77.6 KB Created: 2021-05-29 03:52:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 77cebb9f545b48304adc59ab8f3da978 SHA-1: 9255952b923f8bf0d9df66235b821f40cc05dcc9 SHA-256: 24a181c915ff7640ae5f813b26bfcd1b12d4e3598b84e5ee5a42659cf0e3c070
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are to SEO-optimized content, suggesting a link farm or phishing attempt. The primary URL, https://nipisod.ru/strik?utm_term=recover+deleted+photos+android+free+software, is presented as a resource for recovering deleted photos, a common lure for phishing scams. While no scripts were explicitly extracted, the PDF structure and heuristic firings indicate malicious intent, likely related to directing users to malicious websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://nipisod.ru/strik?utm_term=recover+deleted+photos+android+free+software
    • https://cdn-cms.f-static.net/uploads/4403143/normal_604b4e62c142d.pdf
    • https://cdn-cms.f-static.net/uploads/4370068/normal_6016030a7cbd1.pdf
    • https://fozikubovofow.weebly.com/uploads/1/3/4/8/134897471/3762798.pdf
    • https://sosojisizavawov.weebly.com/uploads/1/3/1/4/131454692/pejurawizinira.pdf
    • https://lomelamul.weebly.com/uploads/1/3/5/9/135994015/61fe34b7.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/474d9437-d723-4390-8663-7596c93d235b/what_is_the_best_sauce_at_taco_bell.pdf
    • https://uploads.strikinglycdn.com/files/f35f55c4-834e-45d1-b73a-dd4498c7e297/71482610797.pdf
    • https://uploads.strikinglycdn.com/files/11d4c15f-c41c-4e53-b407-b0f7b0417475/fiddler_on_the_roof_cast_film.pdf
    • https://uploads.strikinglycdn.com/files/316d1a1d-2b68-437a-ba09-09e37ad600d1/cazadores_de_sombras_renacimiento_4.pdf
    • https://uploads.strikinglycdn.com/files/dc164a9f-e35f-4c1f-9be9-3f53a02798a5/qvc_oreck_air_purifier_filters.pdf
    • https://uploads.strikinglycdn.com/files/f9f11d09-7447-49a5-959b-b09bd619333c/88426285205.pdf
    • https://uploads.strikinglycdn.com/files/b5d93183-d45f-4562-a8ab-9d36939c75ca/95917599443.pdf
    • https://uploads.strikinglycdn.com/files/39f9ed0a-b98a-46ce-831c-fd8219c4a058/tujexopejataninorenowowiz.pdf
    • https://uploads.strikinglycdn.com/files/fd02b866-60b2-4816-ac75-9dfe6074aeb1/short_story_ideas.pdf
    • https://uploads.strikinglycdn.com/files/db34cccc-72f9-46df-a46d-a6587c9e7205/36151664136.pdf
    • https://uploads.strikinglycdn.com/files/a033363e-8e99-4feb-bac3-255c9addaa58/attack_on_titan_movie_1_anime.pdf
    • https://uploads.strikinglycdn.com/files/1094fa99-f90e-4973-ae0a-210b32091222/moon_river_chords.pdf
    • https://uploads.strikinglycdn.com/files/6856b907-02b1-4281-8982-ca073fe27534/2782293170.pdf
    • https://uploads.strikinglycdn.com/files/af4c692a-bcd6-4743-96d4-7598d9c03f6b/cuantos_metros_cuadrados_equivale_un_milimetro_cuadrado.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_off0000f105.bin
c6141959aa7be9d5316b37d5d4d1775f1ed08ee45ae8b909eb1685859c6d0846
pdf-font-stream PDF embedded font (sfnt) at offset 0xF105 5400 bytes
font_01_sfnt_off0001037d.bin
5a996240e3fc15f347211b338a37a7eee11f78e47dcc537888dcfc7d317e2ea7
pdf-font-stream PDF embedded font (sfnt) at offset 0x1037D 10920 bytes