Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5612da66a4b53c8…

MALICIOUS

PDF

74.2 KB Created: 2021-06-03 02:14:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 9d1a4cb6768ef529911927a2d94307c7 SHA-1: 57732d408badcf1668ce506c17f111d6138b14b9 SHA-256: a5612da66a4b53c8ba4c1e48e73d0764b5a65fccb74c549c442931c1b52e9237
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including ClamAV and an ML classifier, indicating malicious intent. The presence of a large number of external links, identified as a 'PDF_SEO_LINK_FARM', suggests a tactic to drive traffic to potentially malicious or deceptive websites. While no scripts were explicitly extracted, the PDF structure and link farm heuristic point towards a phishing or malicious redirection scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://krisoc.ru/pbw?utm_term=free+coaching+tools+pdf
    • https://cdn-cms.f-static.net/uploads/4484612/normal_6052f72b01ffb.pdf
    • https://cdn-cms.f-static.net/uploads/4499651/normal_60b7a1fc0266b.pdf
    • https://cdn-cms.f-static.net/uploads/4486051/normal_605219d8a3bca.pdf
    • https://static.s123-cdn-static-d.com/uploads/4370542/normal_60b3b880df70a.pdf
    • https://cdn-cms.f-static.net/uploads/4495385/normal_601fb4bb04217.pdf
    • https://static.s123-cdn-static.com/uploads/4384632/normal_5febc08a4d86a.pdf
    • https://kusazejur.weebly.com/uploads/1/3/1/4/131437880/8671638.pdf
    • https://kuwepokipeluzil.weebly.com/uploads/1/3/0/9/130969114/4366770.pdf
    • https://cdn-cms.f-static.net/uploads/4477147/normal_602e45b23a8bc.pdf
    • https://cdn-cms.f-static.net/uploads/4486971/normal_6031f366a9fb9.pdf
    • https://wexikapej.weebly.com/uploads/1/3/0/8/130874413/6fef7f4.pdf
    • https://static.s123-cdn-static-d.com/uploads/4366003/normal_60b714cfbe245.pdf
    • https://cdn-cms.f-static.net/uploads/4470826/normal_602ce8b4817c0.pdf
    • https://tamidotojo.weebly.com/uploads/1/3/1/8/131858916/xebalorijekuf.pdf
    • https://pezusadoti.weebly.com/uploads/1/3/4/5/134525395/2579446.pdf
    • https://cdn-cms.f-static.net/uploads/4487641/normal_6039ef4494510.pdf
    • https://static.s123-cdn-static.com/uploads/4417656/normal_60049baf86f13.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/7458d2ae-a6e6-4cf4-a5d9-e0e7819ffe57/the_power_of_positive_thinking_bangla_book_download.pdf
    • https://uploads.strikinglycdn.com/files/00565744-9867-4865-a2bf-4ec9ef885198/xarigubalejufofurafufozav.pdf
    • https://uploads.strikinglycdn.com/files/53377cc8-5274-4398-8aff-1e98abd32d9c/graphic_design_study_guide.pdf
    • https://uploads.strikinglycdn.com/files/e722bb34-089c-49f7-9620-62f318f4dd63/palavuwoxosuxedarisogeno.pdf
    • https://uploads.strikinglycdn.com/files/9d98a1e6-7582-46b3-b895-7866c66c4f51/how_painful_is_arterial_blood_gas_test.pdf
    • https://uploads.strikinglycdn.com/files/f7013f15-c291-4688-a273-2495ce236882/tesegazuf.pdf
    • https://uploads.strikinglycdn.com/files/a1facb97-4484-4469-9e5c-e54589dbea9d/us_army_field_jackets_for_sale.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_off0000e624.bin
5486d80e154d776d8311ff7086785e75a74399c988ccd44e36e5d035e89e09ef
pdf-font-stream PDF embedded font (sfnt) at offset 0xE624 5372 bytes
font_01_sfnt_off0000f867.bin
42164b0367cab1bc5d5fd0fe3f6eeebe7f4eb458044e9c1d4e86afb7c52a80bc
pdf-font-stream PDF embedded font (sfnt) at offset 0xF867 10284 bytes