Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a9a749f4cccbd65…

MALICIOUS

PDF

77.9 KB Created: 2021-04-08 17:53:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-18
MD5: f6668380c7394f8dacce1a13245a130f SHA-1: b4462550a011fef8afbce767e82dcf871ebba0ef SHA-256: 4a9a749f4cccbd65df440b5215823416d150d787ca5770d3e645069025816659
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains a large number of external links, many hosted on disposable domains, suggesting it is part of a link farm designed to redirect users to potentially malicious sites. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and 'Qt', and the presence of external URIs points towards a phishing or redirection attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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://druttle.ru/strik?utm_term=positive+thinking+techniques+in+marathi PDF link annotation
    • https://xejuxomezul.weebly.com/uploads/1/3/1/6/131637030/dc7b2e64.pdfIn PDF document text
    • https://rumirasikimuzib.weebly.com/uploads/1/3/2/7/132710795/46ae4e709e55a9a.pdfIn PDF document text
    • https://cdn.sqhk.co/fukonovum/dibTBS5/fokefuwuxubawikog.pdfIn PDF document text
    • https://sanositew.weebly.com/uploads/1/3/1/8/131872303/pekabuxofodo.pdfIn PDF document text
    • https://cdn.sqhk.co/rotefuver/pRhcjaM/84880154606.pdfIn PDF document text
    • https://povoxiguda.weebly.com/uploads/1/3/4/0/134016665/mugebefuzajusuxol.pdfIn PDF document text
    • https://vufegolafo.weebly.com/uploads/1/3/0/9/130969987/pikorajedujepeti.pdfIn PDF document text
    • https://cdn.sqhk.co/guwezasov/Ihix6ha/45815462181.pdfIn PDF document text
    • https://tujemodi.weebly.com/uploads/1/3/5/3/135301643/putuze.pdfIn PDF document text
    • https://cdn.sqhk.co/konidadelan/EhbLie3/21572725316.pdfIn PDF document text
    • https://webojese.weebly.com/uploads/1/3/0/9/130970005/911889.pdfIn PDF document text
    • https://cdn.sqhk.co/zalivelo/juHT8ih/rubber_snake_on_a_string.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/137a1981-7f5e-4ae9-8ed8-7ca7898fe025/53308144150.pdfIn PDF document text
    • https://eb40363d-1d1f-4170-a897-f23f0f433116.filesusr.com/ugd/2a1429_3218f8882b154bd582133f536e935b20.pdf?index=trueIn PDF document text
    • https://f770b3d7-c897-40e0-9323-5ad0abd91552.filesusr.com/ugd/1fa6dd_b4d05d6dbe954f47a4865ae5dd3f1b5d.pdf?index=trueIn PDF document text
    • https://2d2b1dae-c014-4902-97e6-c3f1d56915cd.filesusr.com/ugd/70e5f7_9d80c4f5fac04f0ca6a2088271c7f832.pdf?index=trueIn PDF document text
    • https://4fd7ac12-06e8-439c-96a9-7636004ccb32.filesusr.com/ugd/9554ab_f2a5a3c5006249deb123d79ca0d96a0a.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/3c0ddf18-c5c7-43d0-9444-721f9dd45444/20686141911.pdfIn PDF document text
    • https://cd70d4e5-4a1a-4071-96d1-f2415ea5ece1.filesusr.com/ugd/7f46b5_967ffdfb2e0348b8b1cf800615e61af4.pdf?index=trueIn PDF document text
    • https://01c19f78-c7d0-441a-b56a-8672493f87de.filesusr.com/ugd/9d66c7_f3cee19bc7ed4ea0aa92ca7e1c4e72f8.pdf?index=trueIn PDF document text
    • https://878ee1be-828d-48b9-a24a-84283cf66a1c.filesusr.com/ugd/86936c_faed65d06d114aebb2099724261b1bd1.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/41421874-b1e2-4de8-9434-71fdd27dccb2/linosu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/600f522b-d6ec-4737-aa15-54ef7aa9205d/how_to_write_a_history_narrative_account.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_off0000ef29.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF29 5432 bytes
SHA-256: a6052bd1e71b732593073d186155292199806f89ff5acf9117903212e3df6714
font_01_sfnt_off00010185.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10185 11312 bytes
SHA-256: 9127dc98c6971dc9558ac37be07966fc81bdfc5dd9de52328b2c5cf85a722fa1