Malicious PDF — malware analysis report

Static analysis result for SHA-256 900dd5effb35be4d…

MALICIOUS

PDF

78.4 KB Created: 2021-03-14 00:36:48 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-17
MD5: 81d5698bef0f64e9babd50d34268d6fc SHA-1: 1b4e5d9093b9cec03e9357b7243aecf02cb4f4cc SHA-256: 900dd5effb35be4d9f3d88d6dbe8e94f33f27831fd22b7477034f8207d95bb78
244 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by ClamAV and an ML classifier. It contains a large number of embedded URLs, functioning as a link farm. One of these URLs, 'https://yafferge.ru/wix?keyword=aok+and+wok+list', is flagged as a known malicious redirector. The PDF's structure and the presence of numerous links suggest an attempt to lure users to malicious sites, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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/wix?keyword=aok+and+wok+list In PDF document text
    • https://paxogusav.weebly.com/uploads/1/3/4/0/134040839/bagisiwasim.pdfIn PDF document text
    • https://xasukibumit.weebly.com/uploads/1/3/4/7/134749231/motoxisekojimud_vonimezuduw.pdfIn PDF document text
    • https://rugadugunat.weebly.com/uploads/1/3/1/6/131606951/kajixaro_tukerojefegaziv.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470207/normal_604463ad8ea37.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366660/normal_6046e6d5a8241.pdfIn PDF document text
    • https://wegoboxup.weebly.com/uploads/1/3/4/7/134772399/weputemagofe.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4466153/normal_6023caf7b6d0d.pdfIn PDF document text
    • https://benanuvez.weebly.com/uploads/1/3/0/8/130813453/7227171.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4389797/normal_6041b529d7df3.pdfIn PDF document text
    • https://dutizadip.weebly.com/uploads/1/3/4/8/134889078/zemogatudetore.pdfIn PDF document text
    • https://selokifasafu.weebly.com/uploads/1/3/4/3/134383977/7134922.pdfIn PDF document text
    • https://farigelud.weebly.com/uploads/1/3/4/2/134266281/faxuxakewe.pdfIn PDF document text
    • https://kuvinobugo.weebly.com/uploads/1/3/1/3/131383931/rejevami-tazubenej-kakevel.pdfIn PDF document text
    • https://penugevofubelig.weebly.com/uploads/1/3/1/1/131164238/1980160.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://3b0fe5ff-7f86-489c-8138-fc984e51136c.filesusr.com/ugd/bfd78a_ceed01d4f714491a9564db3deb5b196f.pdf?index=trueIn PDF document text
    • https://be1d055c-b83b-422e-9e68-1bf13cef350c.filesusr.com/ugd/5b1e3c_9f85aec15d394871bdbe33e5e44c25e5.pdf?index=trueIn PDF document text
    • https://042e50b4-45d0-4577-915a-c14d43ab21ad.filesusr.com/ugd/18f527_8dd67370dea54f2f928af5ac3d8f9a68.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/bezutu/7351226490.pdfIn PDF document text
    • https://s3.amazonaws.com/muwemivumazulax/21809756838.pdfIn PDF document text
    • https://s3.amazonaws.com/vuliwisuwig/15173890787.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_off0000f6ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6ED 4868 bytes
SHA-256: 95a39fa7dce6eb3e53e311eb9e29a57d6365e0413b25099e370acd6fb7fde860
font_01_sfnt_off000107a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107A5 10376 bytes
SHA-256: 95cf79bbd9beb70b087b58d926b352517ed3bdf3157bbf6daaf4ddf1fcec134c