Malicious PDF — malware analysis report

Static analysis result for SHA-256 efcbbdfa4d1ab96a…

MALICIOUS

PDF

104.3 KB Created: 2021-01-24 02:59:45 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-03
MD5: 8b29a4d63672264a20f05b7c81da10f8 SHA-1: 831d3f341178a94fa17236d468e8dca17a2cda91 SHA-256: efcbbdfa4d1ab96a55fd47c8d665ea499be8fbbcd8164db18c7053673cf5679e
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded links pointing to external PDF files hosted on disposable domains, indicating a link farm or SEO manipulation tactic. One critical heuristic identified a link to known malicious redirector infrastructure, suggesting a potential phishing or malware distribution vector. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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/aws?utm_term=whatsapp++for+nokia+asha+210 In PDF document text
    • https://site-1198856.mozfiles.com/files/1198856/colordom_best_color_games_all_in_one.pdfIn PDF document text
    • https://kufesivewafe.weebly.com/uploads/1/3/1/3/131384244/89f755172082.pdfIn PDF document text
    • https://site-1166704.mozfiles.com/files/1166704/58043891080.pdfIn PDF document text
    • https://cdn.sqhk.co/wokuvaxevaji/iihfD0N/badopebawimupisevenodulev.pdfIn PDF document text
    • https://cdn.sqhk.co/rapaxino/akBjbii/earth_zodiac_signs_meanings.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4372707/normal_5ff352ce2f68b.pdfIn PDF document text
    • https://pozusope.weebly.com/uploads/1/3/1/4/131453674/xamosavonibezu-goxopowipu-katabati-xununozabo.pdfIn PDF document text
    • http://nuxefigemotak.22web.org/alpabetong_filipino_worksheet_grade_2.pdfIn PDF document text
    • https://site-1246015.mozfiles.com/files/1246015/40335782659.pdfIn PDF document text
    • https://lugumeduzox.weebly.com/uploads/1/3/0/7/130740149/somomubar.pdfIn PDF document text
    • https://cdn.sqhk.co/namulofilox/fCTibic/konokapikuduburegomazefo.pdfIn PDF document text
    • https://cdn.sqhk.co/bijukipuj/geTiiia/35928465411.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4499636/normal_6008f4f41e6de.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://rabuxudizuxu.epizy.com/23734688932.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_off00015896.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15896 5360 bytes
SHA-256: b306ddd297e6c1d256c0d2882a790d366b17761b7eb63adc25cfbe66e53b7b89
font_01_sfnt_off00016ae2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16AE2 12088 bytes
SHA-256: a70811ff36d09feeaa13a50fcff373f9df642769d4f60d01c4d1712e65dff6b1

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