Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f7fb2f0992c69e2…

MALICIOUS

PDF

68.4 KB Created: 2021-04-13 13:08:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 7ba3b9319f5560b601a9cfcdeebbfac8 SHA-1: cb917be0b9a43429b5320e1e1a4ce7393f0a4bdb SHA-256: 8f7fb2f0992c69e280f67cece5fbddb17f35b7a59e435189ad7db9a585b22dfa
126 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The presence of numerous embedded URLs pointing to various domains, many of which are unknown or suspicious, suggests a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and a 'service manual', which may be part of a social engineering lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://www.enwidth.com/sites/default/files/webform/resumes/paxifufal.pdf In PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/65827293628.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/ginigiwosumomigari.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/dovav.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/fajabenofedutetigolexid.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/58234525485.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/50818196885.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/90703453713.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=bernina+1090+service+manualPDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/febapaxugodikuzakepob.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/wosevojowavinojefe.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/liwubuwivak.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/56905881998.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/20850651402.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c3b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC3B0 2988 bytes
SHA-256: 0f3e660b5db831b6c96bb1b424351db2d90d8ca42e8168593cc8060c393f8d0a
font_01_sfnt_off0000ce4c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE4C 5404 bytes
SHA-256: 8c49088b49c9051ec2fdf4b9027978182c626584a0a36393e5d0ab1896b4d375
font_02_sfnt_off0000e09f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE09F 10648 bytes
SHA-256: 028cded0ce461cadbea9033861e299d9e9b35c5f9349e969c8435a3213bded00

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