Malicious PDF — malware analysis report

Static analysis result for SHA-256 59a4f5951924feae…

MALICIOUS

PDF

76.4 KB Created: 2021-04-14 19:25:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 7bda31125443e107c9dc459f7b61fa41 SHA-1: b52d12ffd63a949804323e1fe734adc642a6d97f SHA-256: 59a4f5951924feae7f13a3fa4d522f6c913d65b74371131c1572411a75304c78
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF file was identified as malicious by multiple heuristics and a machine learning classifier, and also detected by ClamAV. It contains a large number of embedded URLs, many of which point to disposable hosting and appear to be part of a link farm. One URL, 'https://yafferge.ru/strik?utm_term=how+to+steam+vegetables+aroma+rice+cooker', is specifically flagged as a malicious redirector. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/strik?utm_term=how+to+steam+vegetables+aroma+rice+cooker In PDF document text
    • https://cdn-cms.f-static.net/uploads/4383327/normal_60403f8fe1ca9.pdfIn PDF document text
    • http://it50life.pro/annual_report_l_gr79mf.pdfIn PDF document text
    • https://nifirasevaxo.weebly.com/uploads/1/3/4/7/134756957/fevuwufosanagofukok.pdfIn PDF document text
    • https://nubipudovolena.weebly.com/uploads/1/3/4/0/134012318/toxabotat_nogegolanig_diziman_vomiv.pdfIn PDF document text
    • https://vugiwaxe.weebly.com/uploads/1/3/4/7/134739196/3fb96b030aa3.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4480581/normal_5fe102a07412a.pdfIn PDF document text
    • https://nozerazedigil.weebly.com/uploads/1/3/4/3/134309266/38d2c74014.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4493881/normal_6007e51a70322.pdfIn PDF document text
    • https://mavipevawifuduv.weebly.com/uploads/1/3/4/5/134598931/zasupijibido.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4402724/normal_601df9fb90cda.pdfIn PDF document text
    • https://towelekuw.weebly.com/uploads/1/3/1/4/131406253/nomedakedujodo_fafulizugizove.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413573/normal_60292467774eb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4384143/normal_60485fffe56d3.pdfIn PDF document text
    • http://uspeh.icu/97577703891u86b.pdfIn PDF document text
    • https://fevepoxopimumu.weebly.com/uploads/1/3/2/3/132302951/toginumezuti_gebivi_satur.pdfIn PDF document text
    • https://bazusatibewin.weebly.com/uploads/1/3/4/3/134374280/zamivuligelaluje.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/tupofelasujewas/caballo_lake_new_mexico_fishing_report.pdfIn PDF document text
    • https://s3.amazonaws.com/gelawiweza/lutidovebanumu.pdfIn PDF document text
    • https://s3.amazonaws.com/befarekogol/31142855245.pdfIn PDF document text
    • https://s3.amazonaws.com/zobuwubedak/list_the_four_types_of_sentence_structures.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_off0000ec77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC77 5436 bytes
SHA-256: 304952380d3e09bbfbcbe57e0db3ecc02442e0d134443cb54af4c80ad7decc16
font_01_sfnt_off0000fefb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEFB 11076 bytes
SHA-256: 1475e5cc26c8e20909f491a3ebb630c10dc0cf15629061bb49341bf9824fe564